DAPZOI
Home Ask MCQ Quiz Topics Login


Chemical Engineering Thermodynamics MCQ Questions & Answers

Chemical Engineering Thermodynamics MCQs : This section focuses on the "Chemical Engineering Thermodynamics". These Multiple Choice Questions (MCQs) should be practiced to improve the Chemical Engineering Thermodynamics skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

Which of the following is not correct for a reversible adiabatic process?

A. TVγ-1 = constant
B. P1-γ.TY = constant
C. PVγ = constant
D. None of these

View Answer

Question 2

A gas shows deviation from ideal behaviour at

A. Low pressure and high temperature
B. Low pressure and low temperature
C. Low temperature and high pressure
D. High temperature and high pressure

View Answer

Question 3

A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is Φi yi P = Yi xi fi° where, Φ is a vapor fugacity component, Yi is the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of

A. Temperature only
B. Temperature and pressure only
C. Temperature, pressure and liquid composition xi only
D. Temperature, pressure, liquid composition xi and vapour composition yi

View Answer

Question 4

At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the

A. Third law of thermodynamics
B. Second law of thermodynamics
C. Nernst heat theorem
D. Maxwell's relations

View Answer

Question 5

Pick out the wrong statement.

A. The net change in entropy in any reversible cycle is always zero
B. The entropy of the system as a whole in an irreversible process increases
C. The entropy of the universe tends to a maximum
D. The entropy of a substance does not remain constant during a reversible adiabatie change

View Answer

Question 6

Free energy

A. Decreases in all spontaneous (or irreversible) processes
B. Change during a spontaneous process has a negative value
C. Remains unchanged in reversible processes carried at constant temperature and pressure
D. All of the above

View Answer

Question 7

The Maxwell relation derived from the differential expression for the Helmholtz free energy (dA) is

A. (∂T/∂V)S = -(∂P/∂S)V
B. (∂S/∂P)T = -(∂V/∂T)P
C. (∂V/∂S)P = (∂T/∂P)S
D. (∂S/∂V)T = (∂P/∂T)V

View Answer

Question 8

Isentropic process means a constant __________ process.

A. Enthalpy
B. Pressure
C. Entropy
D. None of these

View Answer

Question 9

Heat is added at constant temperature in an ideal __________ cycle.

A. Stirling
B. Brayton
C. Rankine
D. None of these

View Answer

Question 10

Entropy change for an irreversible process taking system and surrounding together is

A. 0
B. > 0
C. < 0
D. None of these

View Answer

Question 11

Internal energy change of a system over one complete cycle in a cyclic process is

A. zero
B. #NAME?
C. #NAME?
D. dependent on the path

View Answer

Question 12

Compressibility factor for almost all the gases are approximately same at the same

A. pressure and temperature.
B. reduced pressure and reduced temperature.
C. critical pressure and critical temperature.
D. none of these.

View Answer

Question 13

In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.

A. 0.25
B. 0.5
C. 0.75
D. 1

View Answer

Question 14

For an irreversible process involving only pressure-volume work

A. (dF)T, p <0
B. (dF)T, p = 0
C. (dF)T, p > 0
D. (dA)T, v >0

View Answer

Question 15

In a turbine, the fluid expands almost

A. Isothermally
B. Isobarically
C. Adiabatically
D. None of these

View Answer

Question 16

In the reaction, represented by, 2SO₂ + O₂ ⇋ 2SO₃; ΔH = - 42 kcal; the forward reaction will be favoured by

A. Low temperature
B. High pressure
C. Both A and B
D. Neither A nor B

View Answer

Question 17

Which of the following is an undesirable characteristics of a refrigerant ?

A. It should be non-explosive
B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
C. Its vapor pressure at the condenser temperature should be very high
D. None of these

View Answer

Question 18

Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as

A. P + F - C = 2
B. C = P - F + 2
C. F = C - P - 2
D. P = F - C - 2

View Answer

Question 19

Pick out the correct statement.

A. Like internal energy and enthalphy, the absolute value of standard entropy for elementary substances is zero
B. Melting of ice involves increase in enthalpy and a decrease in randomness
C. The internal energy of an ideal gas depends only on its pressure
D. Maximum work is done under reversible conditions

View Answer

Question 20

The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x₁. x₂, where A is a constant. The corresponding equation for ln y₁, where y₁ is the activity co-efficient of component 1, is

A. A . x₂²
B. Ax₁
C. Ax₂
D. Ax₁²

View Answer

Question 21

The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.

A. Freezing
B. Triple
C. Boiling
D. Boyle

View Answer

Question 22

Co-efficient of Performance (COP) of a refrigerator is the ratio of the

A. Work required to refrigeration obtained
B. Refrigeration obtained to the work required
C. Lower to higher temperature
D. Higher to lower temperature

View Answer

Question 23

Which of the following is Virial equation of state?

A. (p + a/V²)(V - b) = nRT
B. PV = nRT
C. PV = A + B/V + C/V² + D/V³ + …
D. None of the above

View Answer

Question 24

Law of corresponding states says that

A. , two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same
B. The surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature
C. No gas can be liquified above the critical temperature, howsoever high the pressure may be
D. The molar heat of energy of gas at constant volume should be nearly constant (about 3 calories)

View Answer

Question 25

A domestic refrigerator has a/an __________ cooled condenser.

A. Water
B. Air
C. Evaporative
D. Gas

View Answer

Question 26

Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.

A. Fugacity
B. Partial pressure
C. Activity co-efficient
D. A, B, and C

View Answer

Question 27

Critical compressibility factor for all substances

A. Are more or less constant (vary from 0.2 to 0.3)
B. Vary as square of the absolute temperature
C. Vary as square of the absolute pressure
D. None of these

View Answer

Question 28

On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will

A. Increase
B. Decrease
C. Remain same
D. Increase in summer and will decrease in winter

View Answer

Question 29

In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )

A. addition of inert gas favours the forward reaction, when Δx is positive.
B. pressure has no effect on equilibrium, when Δn = 0.
C. addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero).
D. all 'a', 'b' & 'c'.

View Answer

Question 30

Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will

A. Increase
B. Decrease
C. Remain unchanged
D. First fall and then rise

View Answer

Question 31

The temperature at the eutectic point of the system is the __________ temperature that can be attained in the system.

A. Lowest
B. Highest
C. Average
D. None of these

View Answer

Question 32

Entropy change in case of reversible adiabatic process is

A. Minimum
B. Zero
C. Maximum
D. Indeterminate

View Answer

Question 33

One ton of refrigeration capacity is equivalent to the heat removal rate of

A. 50 k cal/hr
B. 200 BTU/hr
C. 200 BTU/minute
D. 200 BTU/day

View Answer

Question 34

Van Laar equation deals with the activity co-efficients in

A. binary solutions
B. ternary solutions
C. azeotropic mixture only
D. none of these

View Answer

Question 35

Pick out the wrong statement.

A. Activity co-efficient is dimensionless
B. In case of an ideal gas, the fagacity is equal to its pressure
C. In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component
D. The fugacity co-efficient is zero for an ideal gas

View Answer

Question 36

When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is

A. Same in both the phases
B. Zero in both the phases
C. More in vapour phase
D. More in liquid phase

View Answer

Question 37

The most important application of distribution law is in

A. Evaporation
B. Liquid extraction
C. Drying
D. Distillation

View Answer

Question 38

Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole . °K

A. 0
B. ∞
C. 50
D. 100

View Answer

Question 39

Mollier diagram is a plot of

A. Temperature vs. enthalpy
B. Temperature vs. enthalpy
C. Entropy vs. enthalpy
D. Temperature vs. internal energy

View Answer

Question 40

Water on heating from 1 to 4°C

A. contracts
B. expands
C. has same volume
D. may contract or expand

View Answer

Question 41

During a reversible isothermal expansion of an ideal gas, the entropy change is

A. +ve
B. 0
C. -ve
D. ∞

View Answer

Question 42

For an ideal gas, the internal energy depends upon its __________ only.

A. Molecular size
B. Temperature
C. Volume
D. Pressure

View Answer

Question 43

Third law of thermodynamics is concerned with the

A. Value of absolute entropy
B. Energy transfer
C. Direction of energy transfer
D. None of these

View Answer

Question 44

The standard Gibbs free energy change of a reaction depends on the equilibrium

A. Pressure
B. Temperature
C. Composition
D. All of the above

View Answer

Question 45

Isobaric process means a constant process.

A. temperature
B. pressure
C. volume
D. entropy

View Answer

Question 46

First law of thermodynamics deals with the

A. Direction of energy transfer
B. Reversible processes only
C. Irreversible processes only
D. None of these

View Answer

Question 47

In the decomposition of PCl5 represented by, PCl5 ⇋ PCl3 + Cl₂, decrease in the pressure of the system will __________ the degree of dissociation of PCl5.

A. Increase
B. Decrease
C. Not alter
D. None of these

View Answer

Question 48

Which of the following liquid metals has the highest thermal conductivity?

A. Molten sodium
B. Molten lead
C. Mercury
D. Molten potassium

View Answer

Question 49

Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.

A. Below
B. At
C. Above
D. Either B or C

View Answer

Question 50

Which of the following is not an intensive property?

A. Molar heat capacity
B. Internal energy
C. Viscosity
D. None of these

View Answer

Question 51

1st law of thermodynamics is nothing but the law of conservation of

A. momentum
B. mass
C. energy
D. none of these

View Answer

Question 52

As the temperature is lowered towards the absolute zero, the value of the quantity (∂ΔF/∂T) approaches

A. Zero
B. Unity
C. Infinity
D. None of these

View Answer

Question 53

In which of the following reaction equilibria, the value of equilibrium constant Kp will be more than is Kc?

A. 2HI ⇋ H₂ + I₂
B. N₂O₄ ⇋ 2NO₂
C. 2SO₂ + O₂ ⇋ 2SO₃
D. None of these

View Answer

Question 54

In case of the decomposition of hydroiodic acid (2HI ⇋ H₂ + I₂), addition of H₂ (at equilibrium condition) will

A. Increase the partial pressure of I₂
B. Decrease the partial pressure of HI
C. Diminish the degree of dissociation of HI
D. None of these

View Answer

Question 55

What is the value of Joule-Thomson co-efficient for an ideal gas?

A. +ve
B. -ve
C. 0
D. ∞

View Answer

Question 56

Equilibrium constant of a reaction varies with the

A. Initial concentration of the reactant
B. Pressure
C. Temperature
D. None of these

View Answer

Question 57

__________ does not change during phase transformation processes like sublimation, melting & vaporisation.

A. Entropy
B. Gibbs free energy
C. Internal energy
D. All of the above

View Answer

Question 58

Joule-Thomson experiment is

A. Isobaric
B. Adiabatic
C. Isenthalpic
D. Both B & C

View Answer

Question 59

The root mean square speed of molecules of a gas is equal to (where, m = mass of the molecule K = Boltzman's constant, T = absolute temperature)

A. √(2KT/m)
B. √(3KT/m)
C. √(6KT/m)
D. 3KT/m

View Answer

Question 60

Gibbs free energy at constant pressure and temperature under equilibrium conditions is

A. ∞
B. 0
C. Maximum
D. Minimum

View Answer

Question 61

Heat requirement for decomposition of a compound into its elements is __________ that is evolved during the formation of that compound from its elements.

A. The same
B. Less than
C. Greater than
D. Different than

View Answer

Question 62

Equilibrium constant decreases as the temperature

A. Increases, for an exothermic reaction
B. Decreases, for an exothermic reaction
C. Increases, for an endothermic reaction
D. None of these

View Answer

Question 63

Efficiency of a Carnot engine working between temperatures T₁ and T₂ (T₁ < T₂) is

A. (T₂ - T₁)/T₂
B. (T₂ - T₁)/T₁
C. (T₁ - T₂)/T₂
D. (T₁ - T₂)/T₁

View Answer

Question 64

The standard state of a gas (at a given temperature) is the state in which fugacity is equal to

A. Unity
B. Activity
C. Both A & B
D. Neither A nor B

View Answer

Question 65

Dry ice is

A. Moisture free ice
B. Solid helium
C. Solid carbon dioxide
D. None of these

View Answer

Question 66

In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v₁ = 1 m³ and v₂ 3 m³ ) is max imum, when the value of 'n' is

A. 0
B. 1
C. 1.44
D. 1.66

View Answer

Question 67

The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in

A. An open system of constant composition
B. A closed system of constant composition
C. An open system with changes in composition
D. A closed system with changes in composition

View Answer

Question 68

The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is

A. 0
B. ∞
C. +ve
D. -ve

View Answer

Question 69

The expression for entropy change given by, ΔS = nR ln (V₂/V₁) + nCv ln (T₂/T₁) is valid for

A. Reversible isothermal volume change
B. Heating of a substance
C. Cooling of a substance
D. Simultaneous heating and expansion of an ideal gas

View Answer

Question 70

If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.

A. 100
B. 50
C. 205
D. 200

View Answer

Question 71

Which of the following is not affected by temperature changes?

A. Fugacity
B. Activity co-efficient
C. Free energy
D. None of these

View Answer

Question 72

In a working refrigerator, the value of COP is always

A. 0
B. < 0
C. < 1
D. > 1

View Answer

Question 73

What is the value of ln y (where y = activity co-efficient) for ideal gases?

A. Zero
B. Unity
C. Infinity
D. Negative

View Answer

Question 74

Equilibrium constant decreases as the temperature

A. increases, for an exothermic reaction.
B. decreases, for an exothermic reaction.
C. increases, for an endothermic reaction.
D. none of these.

View Answer

Question 75

For a real gas, the chemical potential is given by

A. RT dlnP
B. RT dlnf
C. R dlnf
D. None of these

View Answer

Question 76

In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when

A. N = y = 1.4
B. N = 0
C. N = 1
D. N = 1.66

View Answer

Question 77

Which of the following is a thermodynamic property of a system?

A. Concentration
B. Mass
C. Temperature
D. Entropy

View Answer

Question 78

Pick out the undesirable property for a good refrigerant.

A. High thermal conductivity
B. Low freezing point
C. Large latent heat of vaporisation
D. High viscosity

View Answer

Question 79

Clayperon equation deals with the

A. Rate of change of vapour pressure with temperature
B. Effect of an inert gas on vapour pressure
C. Calculation of ΔF for spontaneous phase change
D. Temperature dependence of heat of phase transition

View Answer

Question 80

Which of the following is a thermodynamic property of a system ?

A. Concentration
B. Mass
C. Temperature
D. Entropy

View Answer

Question 81

Boiling of liquid is accompanied with increase in the

A. Vapor pressure
B. Specific Gibbs free energy
C. Specific entropy
D. All of the above

View Answer

Question 82

4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is

A. 4 J
B. ∞
C. 0
D. 8 J

View Answer

Question 83

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system

A. Its internal energy (U) decreases and its entropy (S) increases
B. U and S both decreases
C. U decreases but S is constant
D. U is constant but S decreases

View Answer

Question 84

Fugacity co-efficient of a substance is the ratio of its fugacity to

A. Mole fraction
B. Activity
C. Pressure
D. Activity co-efficient

View Answer

Question 85

The temperature at which both liquid and gas phases are identical, is called the __________ point.

A. Critical
B. Triple
C. Freezing
D. Boiling

View Answer

Question 86

The following heat engine produces power of 100000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is

A. 100, 000 kW
B. 160, 000 kW
C. 200, 000 kW
D. 320, 000 kW

View Answer

Question 87

The reaction A (l) R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The number of degrees of freedom are

A. 1
B. 2
C. 3
D. 0

View Answer

Question 88

The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by (T₁ - T₂)/T₁. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

A. T₁/(T₁-T₂)
B. T₂/(T₁-T₂)
C. T₁/T₂
D. T₂/R1

View Answer

Question 89

Cv is given by

A. (∂E/∂T)V
B. (∂E/∂V)T
C. (∂E/∂P)V
D. (∂V/∂T)P

View Answer

Question 90

__________ increases with increase in pressure.

A. The melting point of wax
B. The boiling point of a liquid
C. Both A and B
D. Neither A nor B

View Answer

Question 91

Pick out the wrong statement.

A. The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction
B. With increase in temperature, the equilibrium constant increases for an exothermic reaction
C. The equilibrium constant of a reaction depends upon temperature only
D. The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction

View Answer

Question 92

In an ideal gas mixture, fugacity of a species is equal to its

A. Vapor pressure
B. Partial pressure
C. Chemical potential
D. None of these

View Answer

Question 93

In case of a close thermodynamic system, there is __________ across the boundaries.

A. No heat and mass transfer
B. No mass transfer but heat transfer
C. Mass and energy transfer
D. None of these

View Answer

Question 94

The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.

A. Temperature
B. Pressure
C. Composition
D. All of the above

View Answer

Question 95

Entropy is a measure of the __________ of a system.

A. disorder
B. orderly behaviour
C. temperature changes only
D. none of these

View Answer

Question 96

For the gaseous phase chemical reaction, C₂H₄(g) + H₂O(g) ⟷ C₂H₅OH(g), the equilibrium conversion does not depend on the

A. Steam to ethylene ratio
B. Temperature
C. Pressure
D. None of these

View Answer

Question 97

At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by(where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)

A. μ° + RT ln f
B. μ°+ R lnf
C. μ° + T lnf
D. μ° + R/T lnf

View Answer

Question 98

Work done may be calculated by the expression ∫p dA for __________ processes.

A. Non-flow reversible
B. Adiabatic
C. Both A and B
D. Neither A nor B

View Answer

Question 99

Internal energy of an ideal gas

A. Increases with increase in pressure
B. Decreases with increase in temperature
C. Is independent of temperature
D. None of these

View Answer

Question 100

Requisites of a reversible process is that the

A. System and surroundings pressure be equal
B. Friction in the system should be absent
C. System and surroundings temperature be equal
D. None of these

View Answer

Question 101

The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called __________ temperature.

A. Boyle
B. Inversion
C. Critical
D. Reduced

View Answer

Question 102

No work is done by the system, when a reaction occurs at constant

A. volume
B. temperature
C. pressure
D. none of these

View Answer

Question 103

Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions.

A. Ideal
B. Real
C. Isotonic
D. None of these

View Answer

Question 104

The internal energy of an ideal gas is a function of its __________ only.

A. Molecular size
B. Volume
C. Pressure
D. Temperature

View Answer

Question 105

A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid.

A. Subcooled
B. Saturated
C. Non-solidifiable
D. None of these

View Answer

Question 106

The extensive properties are

A. Volume, mass and number of moles
B. Free energy, entropy and enthalpy
C. Both A and B
D. None of these

View Answer

Question 107

Entropy of a substance remains constant during a/an __________ change.

A. Reversible isothermal
B. Irreversible isothermal
C. Reversible adiabatic
D. None of these

View Answer

Question 108

Adiabatic compression of a saturated water vapour makes it

A. Supersaturated
B. Superheated
C. Both A and B
D. Neither A nor B

View Answer

Question 109

The expression for entropy change given by, ΔS = - nR ln (P₂/P₁), holds good for

A. Expansion of a real gas
B. Reversible isothermal volume change
C. Heating of an ideal gas
D. Cooling of a real gas

View Answer

Question 110

The activity of an ideal gas is numerically __________ its pressure.

A. More than
B. Less than
C. Equal to
D. Data insufficient, can't be predicted

View Answer

Question 111

Boyle's law for gases states that

A. , when temperature is constant.
B. , when temperature & mass of the gas remain constant.
C. P ∝ V, at constant temperature & mass of the gas.
D. Err:509

View Answer

Question 112

The necessary condition for phase equilibrium in a multiphase system of N components is that the

A. Chemical potentials of a given component should be equal in all phases
B. Chemical potentials of all components should be same in a particular phase
C. Sum of the chemical potentials of any given component in all the phases should be the same
D. None of these

View Answer

Question 113

Refrigerants commonly used for domestic refrigerators are

A. Ethyl chloride or methyle chloride
B. Freon-12
C. Propane
D. NH₃ or CO₂

View Answer

Question 114

The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is

A. Less
B. More
C. Same
D. Dependent on climatic conditions

View Answer

Question 115

Pick out the wrong statement.

A. Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point
B. Entropy of a system decreases with the evolution of heat
C. Change of internal energy is negative for exothermic reactions
D. The accentric factor for all materials is always more than one

View Answer

Question 116

Third law of thermodynamics is helpful in

A. Prediction of the extent of a chemical reaction
B. Calculating absolute entropies of substances at different temperature
C. Evaluating entropy changes of chemical reaction
D. Both B and C

View Answer

Question 117

Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.

A. 270
B. 327
C. 300
D. 540

View Answer

Question 118

A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is

A. 349
B. 651
C. 667
D. 1000

View Answer

Question 119

If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as

A. Solubility increases as temperature increases
B. Solubility increases as temperature decreases
C. Solubility is independent of temperature
D. Solubility increases or decreases with temperature depending on the Gibbs free energy change of solution

View Answer

Question 120

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the

A. low pressure and high temperature.
B. low pressure and low temperature.
C. high pressure and low temperature.
D. high pressure and high temperature.

View Answer

Question 121

Out of the following refrigeration cycles, which one has maximum COP ?

A. Air cycle
B. Carnot cycle
C. Ordinary vapor compression cycle
D. Vapor compression with a reversible expansion engine

View Answer

Question 122

Which of the following is not an equation of state?

A. Bertholet equation
B. Clausius Clayperon equation
C. Beattie-Bridgeman equation
D. None of these

View Answer

Question 123

Charles' law for gases states that

A. V/T = Constant
B. V ∝ 1/T
C. V ∝ 1/P
D. PV/T = Constant

View Answer

Question 124

The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be

A. More
B. Less
C. Same
D. Data insufficient to predict

View Answer

Question 125

For an isothermal reversible compression of an ideal gas

A. Only ΔE = 0
B. Only ΔH =0
C. ΔE = ΔH = 0
D. DQ = dE

View Answer

Question 126

The accentric factor of a materical, 'ω', is defined as ω = -log10(Prsat)Tr-1 = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always

A. > 2
B. < 1
C. > 1
D. < 3

View Answer

Question 127

Cp of a gas at its critical temperature and pressure

A. Becomes zero
B. Becomes infinity
C. Equals 1 kcal/kmol °K
D. Equals 0.24 kcal/kmol °K

View Answer

Question 128

Degree of freedom of the system ice-water-vapour will be

A. 0
B. 1
C. 2
D. 3

View Answer

Question 129

If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in

A. Volume
B. Enthalpy
C. Both A & B
D. Neither A nor B

View Answer

Question 130

An isentropic process is carried out at constant

A. Volume
B. Pressure
C. Temperature
D. All of the above

View Answer

Question 131

Heat of reaction is

A. Dependent on pressure only
B. Dependent on temperature only
C. Dependent on both pressure and temperature
D. Independent of temperature changes

View Answer

Question 132

A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.

A. Isolated
B. Closed
C. Open
D. None of these

View Answer

Question 133

Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is

A. 300(32/7)
B. 300(33/5)
C. 300(33/7)
D. 300(35/7)

View Answer

Question 134

Heat of reaction at constant volume is identified with __________ change.

A. Enthalpy
B. Internal energy
C. Either A or B
D. Neither A nor B

View Answer

Question 135

A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system are

A. 4
B. 3
C. 5
D. 6

View Answer

Question 136

For an ideal gas, the enthalpy

A. Increases with rise in pressure
B. Decreases with rise in pressure
C. Is independent of pressure
D. Is a path function

View Answer

Question 137

Pick out the correct statement.

A. Compression ratio of an Otto engine is comparatively higher than a diesel engine.
B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
C. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat.
D. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work.

View Answer

Question 138

At absolute zero temperature, the __________ of the gas is zero.

A. Pressure
B. Volume
C. Mass
D. None of these

View Answer

Question 139

What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope?

A. 3
B. 2
C. 1
D. 0

View Answer

Question 140

Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.

A. Infinity
B. Minus infinity
C. Zero
D. None of these

View Answer

Question 141

Duringthe phase transition, __________ changes.

A. Pressure
B. Volume
C. Temperature
D. All of the above

View Answer

Question 142

Fugacity is most helpful in

A. Representing actual behaviour of real gases
B. Representing actual behaviour of ideal gases
C. The study of chemical equilibria involving gases at atmospheric pressure
D. None of these

View Answer

Question 143

In a reversible process

A. Tds = dE + dW
B. DE - dW = Tds
C. DW - dE = Tds
D. Tds - dW + dE >0

View Answer

Question 144

The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is

A. 0
B. +ve
C. -ve
D. ∞

View Answer

Question 145

Fugacity of a component in an ideal gas mixture is euqal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at contant pressure and temperature __________ as its mole fraction increases.

A. Decreases
B. Decreases exponentially
C. Increases
D. Remains constant

View Answer

Question 146

For an ideal gas, the activity co-efficient is

A. Directly proportional to pressure
B. Inversely proportional to pressure
C. Unity at all pressures
D. None of these

View Answer

Question 147

In a homogeneous solution, the activity co-efficient of a component depends upon the

A. Pressure
B. Composition
C. Temperature
D. All of the above

View Answer

Question 148

Pick out the wrong statement.

A. The values of (∂P/∂V)T and (∂²P/∂V²)T are zero for a real gas at its critical point
B. Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process
C. Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures
D. During a reversible adiabatic process, the entropy of a substance remains constant

View Answer

Question 149

A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.

A. 2.73
B. 28.3
C. 273
D. 283

View Answer

Question 150

Joule-Thomson experiment is

A. isobaric
B. adiabatic
C. isenthalpic
D. both(b) & (c)

View Answer

Question 151

When dilute aqueous solutions of two salts are mixed, the process is associated with

A. Decrease in temperature
B. Increase in temperature
C. No change in temperature
D. Change in temperature which is a function of composition

View Answer

Question 152

Which of the following has the least thermal efficiency?

A. Steam engine
B. Carnot engine
C. Diesel engine
D. Otto engine

View Answer

Question 153

The chemical potential for a pure substance is __________ its partial molal free energy.

A. More than
B. Less than
C. Equal to
D. Not related to

View Answer

Question 154

Which of the following exemplifies an adiabatic process?

A. Melting of ice
B. Condensation of alcohol vapor
C. Sudden bursting of a cycle tube
D. Evaporation of water

View Answer

Question 155

Rotary lime kiln is an example of a/an __________ system.

A. Closed
B. Open
C. Isolated
D. Non-thermodynamic

View Answer

Question 156

The shape of T-S diagram for Carnot Cycle is a

A. Rectangle
B. Rhombus
C. Trapezoid
D. Circle

View Answer

Question 157

The minimum number of phases that can exist in a system is

A. 0
B. 1
C. 2
D. 3

View Answer

Question 158

The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is

A. Less pronounced
B. More pronounced
C. Equal
D. Data insufficient, can't be predicted

View Answer

Question 159

In a homogeneous solution, the fugacity of a component depends upon the

A. Pressure
B. Composition
C. Temperature
D. All of the above

View Answer

Question 160

Joule-Thomson effect i.e., a throttling process is a constant __________ process.

A. Entropy
B. Temperature
C. Internal energy
D. Enthalpy

View Answer

Question 161

dW and dq are not the exact differential, because q and W are

A. State functions
B. Path functions
C. Intensive properties
D. Extensive properties

View Answer

Question 162

Two substances are in equilibrium in a reversible chemical reaction. If the concentration of each substance is doubled, then the value of the equilibrium constant will be

A. Same
B. Doubled
C. Halved
D. One fourth of its original value

View Answer

Question 163

Free energy change of mixing two liquid substances is a function of the

A. Concentration of the constituents only
B. Quantities of the constituents only
C. Temperature only
D. All of the above

View Answer

Question 164

The compressibility factor for an ideal gas is 1. Its value for any other real gas is

A. 1
B. < 1
C. > 1
D. Either (b) or (c), depends on the nature of the gas

View Answer

Question 165

Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 ⇋ PCl3 + Cl₂.Degree of dissociation of PCl5 will

A. Decrease on addition of Cl₂
B. Increase on addition of an inert gas at constant pressure
C. Decrease on increasing the pressure of the system
D. None of these

View Answer

Question 166

In polytropic process (PVn = constant), if n = 1; it means a/an __________ process.

A. Adiabatic
B. Reversible
C. Isothermal
D. None of these

View Answer

Question 167

PVy = constant, holds good for an isentropic process, which is

A. Reversible and isothermal
B. Isothermal and irreversible
C. Reversible and adiabatic
D. Adiabatic and irreversible

View Answer

Question 168

Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is

A. Positive
B. Negative
C. Zero
D. Infinity

View Answer

Question 169

The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.

A. Critical
B. Boyle
C. Inversion
D. Reduced

View Answer

Question 170

Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates

A. Use of only one graph for all gases
B. Covering of wide range
C. Easier plotting
D. More accurate plotting

View Answer

Question 171

Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a

A. Straight line
B. Sine curve
C. Parabola
D. Hyperbola

View Answer

Question 172

Gibbs phase rule finds application, when heat transfer occurs by

A. Conduction
B. Convection
C. Radiation
D. Condensation

View Answer

Question 173

With increase in pressure (above atmospheric pressure), the Cp of a gas

A. Increases
B. Decreases
C. Remains unchanged
D. First decreases and then increases

View Answer

Question 174

Linde gas liquefaction process employs cooling

A. by throttling
B. by expansion in an engine
C. at constant pressure
D. none of these

View Answer

Question 175

Trouton's ratio of __________ liquids is calculated using Kistyakowsky equation.

A. Polar
B. Non-polar
C. Both A & B
D. Neither A nor B

View Answer

Question 176

Normal temperature and pressure (N.T.P.) corresponds to

A. 0°C and 760 mm Hg
B. 15°C and 760 mm Hg
C. 20°C and 760 mm Hg
D. 0°C and 1 kgf/cm²

View Answer

Question 177

The kinetic energy of gas molecule is zero at

A. 0°C
B. 273°C
C. 100°C
D. -273°C

View Answer

Question 178

A large iceberg melts at the base, but not at the top, because of the reason that

A. Ice at the base contains impurities which lowers its melting point
B. Due to the high pressure at the base, its melting point reduces
C. The iceberg remains in a warmer condition at the base
D. All of the above

View Answer

Question 179

Equation which relates pressure, volume and temperature of a gas is called the

A. Equation of state
B. Gibbs Duhem equation
C. Ideal gas equation
D. None of these

View Answer

Question 180

Air-refrigeration cycle

A. Is the most efficient of all refrigeration cycles
B. Has very low efficiency
C. Requires relatively large quantities of air to achieve a significant amount of refrigeration
D. Both B and C

View Answer

Question 181

Activity co-efficient is a measure of the

A. Departure from ideal solution behaviour
B. Departure of gas phase from idea] gas law
C. Vapour pressure of liquid
D. None of these

View Answer

Question 182

In jet refrigerators, the refrigerating fluid is practically always

A. water
B. ammonia
C. freon
D. brine

View Answer

Question 183

For spontaneous changes in an isolated system (S = entropy)

A. Ds = 0
B. Ds <0
C. Ds > 0
D. Ds = Constant

View Answer

Question 184

Choose the condition that must be specified in order to liquify CO₂ (triple point for CO₂ is - 57°C and 5.2 atm).

A. Pressure must be kept below 5.2 atm
B. Temperature must be kept above - 57°C
C. Pressure must be kept below 5.2 atm. and temperature must be kept above 57°C
D. Pressure and temperature must be kept below 5.2 atm. and - 57°C respectively

View Answer

Question 185

Entropy of the system decreases, when

A. Snow melts into water
B. A gas expands spontaneously from high pressure to low pressure
C. Water is converted into ice
D. Both B & C

View Answer

Question 186

Which of the following is true for Virial equation of state?

A. Virial co-efficients are universal constants
B. Virial co-efficients
C. Virial co-efficients are function of temperature only
D. For some gases, Virial equations and ideal gas equations are the same

View Answer

Question 187

Entropy of an ideal gas depends upon its

A. pressure
B. temperature
C. both (a) & (b)
D. neither (a) nor (b)

View Answer

Question 188

In the equation, PVn = constant, if the value of n is in between 1 and y (i.e. Cp/Cv), then it represents a reversible __________ process.

A. Isometric
B. Polytropic
C. Isentropic
D. Isobaric

View Answer

Question 189

Work done in case of free expansion is

A. Indeterminate
B. Zero
C. Negative
D. None of these

View Answer

Question 190

Which of the following is an extensive property of a system?

A. Heat capacity
B. Molal heat capacity
C. Pressure
D. Concentration

View Answer

Question 191

A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is

A. zero
B. positive
C. negative
D. none of these

View Answer

Question 192

Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The reatio of chemical potential to free energy of a pure substance at oconstant temperature and pressure is

A. 0
B. 1
C. ∞
D. None of these

View Answer

Question 193

Generation of heat by friction is an example of a/an __________ change.

A. Isothermal
B. Irreversible
C. Adiabatic
D. Reversible

View Answer

Question 194

For an isothermal process, the internal energy of a gas

A. Increases
B. Decreases
C. Remains unchanged
D. Data insufficient, can't be predicted

View Answer

Question 195

A change in state involving a decrease in entropy can be spontaneous, only if

A. It is exothermic
B. It is isenthalpic
C. It takes place isothermally
D. It takes place at constant volume

View Answer

Question 196

The equation, PV = nRT, is best obeyed by gases at

A. Low pressure & high temperature
B. High pressure & low temperature
C. Low pressure & low temperature
D. None of these

View Answer

Question 197

Claussius-Clayperon equation gives accurate result, when the

A. Vapour pressure is relatively low and the temperature does not vary over wide limits
B. Vapour obeys the ideal gas law and the latent heat of vaporisation is constant
C. Volume in the liquid state is negligible compared with that in the vapour state
D. All of the above

View Answer

Question 198

Melting of ice exemplifies a/an

A. Adiabatic process
B. Endothermic reaction
C. Exothermic reaction
D. Process involving a chemical reaction

View Answer

Question 199

The Joule-Thomson co-efficient is defined as (∂T/∂P)H. Its value at the inversion point is

A. ∞
B. 1
C. 0
D. -ve

View Answer

Question 200

For a given substance at a specified temperature, activity is __________ to fugacity.

A. Directly proportional
B. Inversely proportional
C. Equal
D. None of these

View Answer

Question 201

Enthalpy 'H' is defined as

A. H = E - PV
B. H = F - TS
C. H - E = PV
D. None of these

View Answer

Question 202

Claude gas liquefaction process employs cooling

A. At constant pressure
B. By throttling
C. By expansion in an engine
D. None of these

View Answer

Question 203

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

A. Maxwell's equation
B. Clayperon-Claussius equation
C. Van Laar equation
D. Nernst Heat Theorem

View Answer

Question 204

Which is an example of closed system?

A. Air compressor
B. Lquid cooling system of an automobile
C. Boiler
D. None of these

View Answer

Question 205

Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).

A. Entropy
B. Internal energy
C. Enthalpy
D. Gibbs free energy

View Answer

Question 206

Melting of ice is an example of an __________ process.

A. Adiabatic
B. Isothermal
C. Isometric
D. None of these

View Answer

Question 207

The gas law (PV = RT) is true for an __________ change.

A. Isothermal
B. Adiabatic
C. Both A & B
D. Neither A nor B

View Answer

Question 208

A system in which there is exchange of energy but not of mass, is called a/an __________ system.

A. Isolated
B. Open
C. Insulated
D. Closed

View Answer

Question 209

An irreversible process

A. Is the analog of linear frictionless motion in machines
B. Is an idealised visualisation of behaviour of a system
C. Yields the maximum amount of work
D. Yields an amount of work less than that of a reversible process

View Answer

Question 210

The change in Gibbs freee energy for vaporisation of a pure substance is

A. Positive
B. Negative
C. Zero
D. May be positive or negative

View Answer

Question 211

A gas performs the maximum work, when it expands

A. Non-uniformly
B. Adiabatically
C. Isobarically
D. Isothermally

View Answer

Question 212

Heat of formation of an element in its standard state is

A. 0
B. < 0
C. > 0
D. A function of pressure

View Answer

Question 213

A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?

A. Vapor compression cycle using expansion valve
B. Air refrigeration cycle
C. Vapor compression cycle using expansion engine
D. Carnot refrigeration cycle

View Answer

Question 214

Pick out the wrong statement.

A. A refriferation cycle violates the second law of thermadynamics
B. Refrigeration cycle is normally represented by a temperature vs. entropy plot
C. In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases
D. One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

View Answer

Question 215

The work done in isothermal compression compared to that in adiabatic compression will be

A. Less
B. More
C. Same
D. More or less depending upon the extent of work done

View Answer

Question 216

While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is

A. Infinity
B. Unity
C. Constant
D. Negative

View Answer

Question 217

Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.

A. 0
B. 273
C. 25
D. None of these

View Answer

Question 218

Degress of freedom at triple point will be

A. 0
B. 1
C. 2
D. 3

View Answer

Question 219

Internal energy change of a system over one complete cycle in a cyclic process is

A. Zero
B. +ve
C. -ve
D. Dependent on the path

View Answer

Question 220

Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the

A. Calorific value
B. Heat of reaction
C. Heat of combustion
D. Heat of formation

View Answer

Question 221

The internal energy of a gas obeying P (V - b) RT (where, b is a positive constant and has a constant Cv), depends upon its

A. Pressure
B. Volume
C. Temperature
D. All of the above

View Answer

Question 222

The thermodynamic law, PVy = constant, is not applicable in case of

A. Ideal compression of air
B. Free expansion of an ideal gas
C. Adiabatic expansion of steam in a turbine
D. Adiabatic compression of a perfect gas

View Answer

Question 223

A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P₁ and P₂.(where, P₁ and P₂ are initial and final pressures respectively)

A. Logarithmic
B. Arithmetic
C. Geometric
D. Harmonic

View Answer

Question 224

"At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero". This follows from the

A. third law of thermodynamics
B. second law of thermodynamics
C. Nernst heat theorem
D. Maxwell's relations

View Answer

Question 225

The intensive properties are

A. Molar volume, density, viscosity and boiling point
B. Refractive index and surface tension
C. Both A and B
D. None of these

View Answer

Question 226

Which of the following is not an intensive property?

A. Volume
B. Density
C. Temperature
D. Pressure

View Answer

Question 227

Any substance above its critical temperature exists as

A. Saturated vapour
B. Solid
C. Gas
D. Liquid

View Answer

Question 228

Lenz's law results from the law of conservation of

A. Mass
B. Momentum
C. Energy
D. None of these

View Answer

Question 229

The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process.

A. Isobaric
B. Isothermal
C. Adiabatic
D. None of these

View Answer

Question 230

When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is

A. More in vapour phase
B. More in liquid phase
C. Same in both the phases
D. Replaced by chemical potential which is more in vapour phase

View Answer

Question 231

__________ law of thermodynamics ascertains the direction of a particular spontaneous process.

A. Zeroth
B. First
C. Second
D. Third

View Answer

Question 232

Gibbs-Duhem equation

A. States that n₁dμ₁ + n₂dμ₂ + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
B. Applies only to binary systems
C. Finds no application in gas-liquid equilibria involved in distillation
D. None of these

View Answer

Question 233

The internal energy of an ideal gas does not change in a reversible __________ process.

A. Isothermal
B. Adiabatic
C. Isobaric
D. Isometric

View Answer

Question 234

Compressibility factor for almost all the gases are approximately same at the same

A. Pressure and temperature
B. Reduced pressure and reduced temperature
C. Critical pressure and critical temperature
D. None of these

View Answer

Question 235

At the critical point of a substance

A. The surface tension vanishes
B. Liquid and vapour have the same density
C. There is no distinction between liquid and vapour phases
D. All of the above

View Answer

Question 236

It is desired to bring about a certain change in the state of a system by performing work on the system under adiabatic conditions.

A. The amount of work needed is path dependent
B. Work alone can not bring out such a change of state
C. The amount of work needed is independent of path
D. More information is needed to conclude anything about the path dependence or otherwise of the work needed

View Answer

Question 237

The compressibility factor of a gas is given by (where, V₁ = actual volume of the gas V₂ = gas volume predicted by ideal gas law )

A. V₁/V₂
B. V₂/V₁
C. V₁-V₂
D. V₁.V₂

View Answer

Question 238

Partial molal quantities are important in the study of

A. Ideal gases
B. Ideal solutions
C. Non-ideal mixtures
D. A pure component

View Answer

Question 239

The first law of thermodynamics is a statement of conservation of

A. Heat
B. Momentum
C. Energy
D. Work

View Answer

Question 240

Reduced pressure of a gas is the ratio of its

A. Pressure to critical pressure
B. Critical pressure to pressure
C. Pressure to pseudocritical pressure
D. Pseudocritical pressure to pressure

View Answer

Question 241

The value of Cp & Cv respectively for monoatomic gases in Kcal/kg Mole . °K are

A. 5 & 3
B. 3.987 & 1.987
C. 1.987 & 0.66
D. 0.66 & 1.987

View Answer

Question 242

Entropy change of mixing two liquid substances depends upon the

A. Molar concentration
B. Quantity (i.e. number of moles)
C. Both A and B
D. Neither A nor B

View Answer

Question 243

Absolute zero temperature signifies the

A. Minimum temperature attainable
B. Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in
C. Temperature of the heat reservoir to which a Carnot engine rejects no heat
D. None of these

View Answer

Question 244

Gibbs free energy (F) is defined as

A. F = E - TS
B. F = H - TS
C. F = H + TS
D. F = E + TS

View Answer

Question 245

Sound waves propagation in air exemplifies an __________ process.

A. Adiabatic
B. Isothermal
C. Isometric
D. None of these

View Answer

Question 246

A refrigerator may be termed as a

A. heat pump
B. heat engine
C. Carnot engine
D. none of these

View Answer

Question 247

Enthalpy changes over a constant pressure path are always zero for __________ gas.

A. Any
B. A perfect
C. An easily liquefiable
D. A real

View Answer

Question 248

At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.

A. 72
B. 92
C. 142
D. 192

View Answer

Question 249

Throttling (Joule-Thomson effect) process is a constant __________ process.

A. Enthalpy
B. Entropy
C. Pressure
D. None of these

View Answer

Question 250

Pick out the correct statement.

A. A real gas on expansion in vacuum gets heated up
B. An ideal gas on expansion in vacuum gets cooled
C. An ideal gas on expansion in vacuum gets heated up
D. A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected

View Answer

Question 251

In an ideal solution, the activity of a component equals its

A. Mole fraction
B. Fugacity at the same temperature and pressure
C. Partial pressure
D. None of these

View Answer

Question 252

If the internal energy of an ideal gas decreases by the same amount as the work done by the system, then the

A. Process must be isobaric
B. Temperature must decrease
C. Process must be adiabatic
D. Both B and C

View Answer

Question 253

Sublimation temperature of dry ice (solid CO₂) is __________ °C.

A. -273
B. 0
C. -78
D. 5

View Answer

Question 254

__________ functions are exemplified by heat and work.

A. Path
B. Point
C. State
D. None of these

View Answer

Question 255

Pick out the wrong statement.

A. A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy
B. An open system permits exchange of both mass and energy with its surroundings
C. The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics
D. None of the above

View Answer

Question 256

The expression, ΔG = nRT .In P₂/P₁ , gives the free energy change

A. With pressure changes at constant temperature
B. Under reversible isothermal volume change
C. During heating of an ideal gas
D. During cooling of an ideal gas

View Answer

Question 257

When pressure is applied on the system, ice ⟷ water, then

A. Equilibrium can not be established
B. More ice will be formed
C. More water will be formed
D. Evaporation of water will take place

View Answer

Question 258

Solid and liquid phases of a substance are in equilibrium at the

A. Critical temperature
B. Melting point
C. Freezing point
D. Both B and C

View Answer

Question 259

Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is

A. Slower than Y
B. Faster than Y
C. Three times slower than Y
D. Three times faster than Y

View Answer

Question 260

In the ammonia synthesis reaction, N₂ + 3H₂ ⇋ 2NH₃ + 22.4 kcal, the formation of NH₃ will be favoured by

A. High temperature
B. Low pressure
C. Low temperature only
D. Both low temperature and high pressure

View Answer

Question 261

For organic compounds, group contribution method can be used for the estimation of

A. Critical properties
B. Specific gravity
C. Specific volume
D. Thermal conductivity

View Answer

Question 262

For the reversible exothermic reaction, N₂ + 3H₂ ⇋ 2NH₃, increase of pressure would

A. Shift the equilibrium towards right
B. Give higher yield of NH₃
C. Both B and C
D. Neither A nor B

View Answer

Question 263

If atmospheric temperature and dew point are nearly equal, then the relative humidity is

A. Zero
B. 50%
C. Almost 100%
D. Unpredictable

View Answer

Question 264

The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the

A. Lewis-Randall rule
B. Statement of Vant-Hoff equation
C. Le-Chatelier's principle
D. None of these

View Answer

Question 265

The amount of heat required to decompose a compound into its elements is __________ the heat of formation of that compound from its elements.

A. Less than
B. More than
C. Same as
D. Not related to

View Answer

Question 266

Pick out the wrong statement.

A. Phase rule variables are intensive properties
B. Heat and work are both state function
C. The work done by expansion of a gas in vacuum is zero
D. CP and CV are state function

View Answer

Question 267

Clausius - Clayperon equation is applicable to __________ equilibrium processes.

A. Solid-vapor
B. Solid-liquid
C. Liquid-vapor
D. All of the above

View Answer

Question 268

A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect ?

A. Vapor compression cycle using expansion valve.
B. Air refrigeration cycle.
C. Vapor compression cycle using expansion engine.
D. Carnot refrigeration cycle.

View Answer

Question 269

Which of the following is not a common refrigerant?

A. Freon-12
B. Ethylene
C. Ammonia
D. Carbon dioxide

View Answer

Question 270

Pick out the correct statement:

A. In an isothermal system, irreversible work is more than reversible work
B. Under reversible conditions, the adiabatic work is less than isothermal work
C. Heat, work, enthalpy and entropy are all 'state functions'
D. Matter and energy can not be exchanged with the surroundings in a closed system

View Answer

Question 271

For an ideal liquid solution, which of the following is unity?

A. Activity
B. Fugacity
C. Activity co-efficient
D. Fugacity co-efficient

View Answer

Question 272

Thermal efficiency of a Carnot engine can approach 100%, only when the temperature of the

A. Cold reservoir approaches zero
B. Hot reservoir approaches infinity
C. Either A or B
D. Neither A nor B

View Answer

Question 273

For a reversible process involving only pressure-volume work

A. (dF)T, p < 0
B. (dF)T, p > 0
C. (dF)T, p = 0
D. (dA)T, v < 0

View Answer

Question 274

Entropy change of the reaction, H₂O(liquid) H₂O(gas), is termed as the enthalpy of

A. Solution
B. Vaporisation
C. Formation
D. Formation

View Answer

Question 275

In case of an __________ process, the temperature of the system increases.

A. Isothermal compression
B. Isothermal expansion
C. Adiabatic expansion
D. Adiabatic compression

View Answer

Question 276

A nozzle is a device, which

A. Increases kinetic energy and decreases pressure
B. Reduces kinetic energy and increases pressure
C. Reduces both kinetic energy and pressure
D. Increases both kinetic energy and pressure

View Answer

Question 277

Heating of water under atmospheric pressure is an __________ process.

A. isochoric
B. isobaric
C. adiabatic
D. isothermal

View Answer

Question 278

Henry's law is closely obeyed by a gas, when its __________ is extremely high.

A. Pressure
B. Solubility
C. Temperature
D. None of these

View Answer

Question 279

Cp - Cv = R is valid for __________ gases.

A. Ideal
B. All
C. Very high pressure
D. Very low temperature

View Answer

Question 280

Helmholtz free energy (A) is defined as

A. A = H - TS
B. A = E - TS
C. A = H + TS
D. None of these

View Answer

Question 281

The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.

A. kinematic viscosity
B. work
C. temperature
D. none of these

View Answer

Question 282

For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is

A. X
B. X + 1
C. X + 2
D. X + 3

View Answer

Question 283

Cv for an ideal gas

A. Does not depend upon temperature
B. Is independent of pressure only
C. Is independent of volume only
D. Is independent of both pressure and volume

View Answer

Question 284

The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.

A. Internal energy
B. Enthalpy
C. Gibbs free energy
D. Helmholtz free energy

View Answer

Question 285

Fugacity is a measure of the

A. Escaping tendencies of the same substance in different phases of a system
B. Relative volatility of a mixture of two miscible liquids
C. Behaviour of ideal gases
D. None of these

View Answer

Question 286

Which is not a refrigerant?

A. SO₂
B. NH₃
C. CCl₂F₂
D. C₂H₄Cl₂

View Answer

Question 287

At 60° C, vapour pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60° C exerts a pressure of 39.223 kPa; the liquid phase and vapour phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is

A. 1.572
B. 1.9398
C. 3.389
D. 4.238

View Answer

Question 288

During Joule-Thomson expansion of gases

A. Enthalpy remains constant
B. Entropy remains constant
C. Temperature remains constant
D. None of these

View Answer

Question 289

During adiabatic expansion of gas

A. Pressure remains constant
B. Pressure is increased
C. Temperature remains constant
D. None of these

View Answer

Question 290

The expression, nRT In P₁/P₂ , is for the____of an ideal gas.

A. Compressibility
B. Work done under adiabatic contition
C. Work done under isothermal condition
D. Co-efficient of thermal expansion

View Answer

Question 291

All gases above its inversion temperature, in a throttling process will show

A. A heating effect
B. No change in temperature
C. A cooling effect
D. Either A or C

View Answer

Question 292

Kopp's rule is used to calculate the heat capacity of

A. Solids
B. Liquids
C. Gases
D. All of the above

View Answer

Question 293

The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are

A. Zero
B. One
C. Two
D. Three

View Answer

Question 294

A solute distributes itself between two non-miscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount". This is

A. The distribution law
B. Followed from Margule's equation
C. A corollary of Henry's law
D. None of these

View Answer

Question 295

In any spontaneous process,

A. only F decreases
B. only A decreases
C. both F and A decreases
D. both F and A increase

View Answer

Question 296

The unity of Planck's constant 'h' in the equation, E = hv is

A. J/s
B. J.S
C. J/kmol
D. Kmol/J

View Answer

Question 297

For a cyclic process, a fixed ratio between heat and work

A. Always exists
B. May exist
C. Never exists
D. Is difficult to predict

View Answer

Question 298

Pick out the extensive property out of the following.

A. Surface tension
B. Free energy
C. Specific heat
D. Refractive index

View Answer

Question 299

The total change in the enthalpy of a system is independent of the

A. Number of intermediate chemical reactions involved
B. Pressure and temperature
C. State of combination and aggregation in the beginning and at the end of the reaction
D. None of these

View Answer

Question 300

Pick out the correct statement:

A. In an isothermal system, irreversible work is more than reversible work.
B. Under reversible conditions, the adiabatic work is less than isothermal work.
C. Heat, work, enthalpy and entropy are all 'state functions'.
D. Matter and energy can not be exchanged with the surroundings in a closed system.

View Answer

Question 301

The specific heat of saturated water vapour at 100°C is

A. ∞
B. -ve
C. 0
D. +ve

View Answer

Question 302

A refrigeration cycle is the same as a __________ cycle,

A. Turbine
B. Heat engine
C. Reversed heat engine
D. None of these

View Answer

Question 303

Specific/molar Gibbs free energy for a pure substance does not change during

A. Sublimation
B. Vaporisation
C. Melting
D. Either A, B or C

View Answer

Question 304

Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg . K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is

A. Superheated vapour
B. Partially condensed vapour with quality of 0.9
C. Saturated vapour
D. Partially condensed vapour with quality of 0.1

View Answer

Question 305

Change of state namely evaportation condensation, freezing and melting is an __________ process.

A. Isothermal
B. Adiabatic
C. Isobaric
D. Isochoric

View Answer

Question 306

Joule-Thomson Co-efficient at any point on the inversion curve is

A. ∞
B. + ve
C. 0
D. -ve

View Answer

Question 307

For a constant volume process __________ by the system is used only to increase the internal energy.

A. Heat absorbed
B. Work done
C. Both A & B
D. Neither A nor B

View Answer

Question 308

A system is said to be isopiestic, if there is no __________ change.

A. Temperature
B. Pressure
C. Volume
D. None of these

View Answer

Question 309

The first law of thermodynamics is a restatement of the law of conservation of

A. Mass
B. Energy
C. Momentum
D. None of these

View Answer

Question 310

The heat capacities for the ideal gas state depend upon the

A. Pressure
B. Temperature
C. Both A & B
D. Neither A nor B

View Answer

Question 311

The energy of activation of exothermic reaction is

A. Zero
B. Negative
C. Very large compared to that for en-dothermic reaction
D. Not possible to predict

View Answer

Question 312

As the time is passing, entropy of the universe

A. Is increasing
B. Is decreasing
C. Remains constant
D. Data insufficient, can't be predicted

View Answer

Question 313

High __________ is an undesirable property for a good refrigerant.

A. specific heat
B. latent heat of vaporisation
C. viscosity
D. specific vapor volume

View Answer

Question 314

The quantitative effect of temperature on chemical equilibrium is given by the

A. Vant-Hoff equation
B. Le-Chatelier's principle
C. Arhenius equation
D. None of these

View Answer

Question 315

In an irreversible process

A. Tds = dE - dW = 0
B. DE - dW - Tds = 0
C. Tds - dE + dW< 0
D. Tds - dT + dW< 0

View Answer

Question 316

Which is a state function?

A. Specific volume
B. Work
C. Pressure
D. Temperature

View Answer

Question 317

The work done in an adiabatic change in a particular gas depends upon changes in the __________ only.

A. Temperature
B. Specific heat
C. Volume
D. Pressure

View Answer

Question 318

The equation relating E, P, V and T which is true for all substanes under all conditions is given by (∂E/∂V)T = T.(∂P/∂T)H - P . This equation is called the

A. Maxwell
B. Thermodynamic equation of state
C. Equation of state
D. Redlich-Kwong equation of state

View Answer

Question 319

Which of the following is not an intensive property ?

A. Chemical potential
B. Surface tension
C. Heat capacity
D. None of these

View Answer

Question 320

Heat pump

A. Accomplishes only space heating in winter
B. Accomplishes only space cooling in summer
C. Accomplishes both A and B
D. Works on Carnot cycle

View Answer

Question 321

Which of the following decreases with increase in pressure?

A. Melting point of ice
B. Melting point of wax
C. Boiling point of liquids
D. None of these

View Answer

Question 322

Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.

A. 1st
B. zeroth
C. 3rd
D. none of these

View Answer

Question 323

The melting point of paraffin wax (which contracts on solidification) __________ with pressure rise.

A. Increases
B. Decreases
C. Remains unchanged
D. Decreases linearly

View Answer

Question 324

Domestic refrigerator usually works on the __________ refrigeration cycle.

A. Carnot
B. Air
C. Absorption
D. Vapour-ejection

View Answer

Question 325

Which of the following non-flow reversible compression processes require maximum work?

A. Adiabatic process
B. Isothermal process
C. Isobaric process
D. All of the above

View Answer

Question 326

The expression for entropy change, ΔS = n Cp . ln (T₂/T₁), is valid for the __________ of a substance.

A. Simultaneous pressure & temperature change
B. Heating
C. Cooling
D. Both B and C

View Answer

Question 327

The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.

A. Contracts
B. Expands
C. Does not change in volume
D. Either A, B or C

View Answer

Question 328

The ammonia synthesis reaction represented by N₂ + 3H₂ ⇋ 2NH₃ ; ΔH = - 22.4 kcal, is

A. Endothermic
B. Exothermic
C. Isothermal
D. Adiabatic

View Answer

Question 329

As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches

A. Zero
B. Unity
C. Infinity
D. An indeterminate value

View Answer

Question 330

Entropy is a/an

A. State function
B. Macroscopic property
C. Extensive property
D. None of these

View Answer

Question 331

In the reaction; N₂ + O₂ ⇋ 2NO, increasing the pressure will result in

A. Shifting the equilibrium towards right
B. Shifting the equilibrium towards left
C. No change in equilibrium condition
D. None of these

View Answer

Question 332

In the equation, PVn = Constant, if the value of n = 0, then it represents a reversible __________ process.

A. Isobaric
B. Isothermal
C. Isentropic
D. Isometric

View Answer

Question 333

Out of the following refrigration cycles, which one has the minimum COP (Co-efficient of performance)?

A. Air cycle
B. Carnot cycle
C. Ordinary vapour compression cycle
D. Vapour compression with a reversible expansion engine

View Answer

Question 334

Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is

A. 1
B. 4
C. 2
D. 3

View Answer

Question 335

Refrigeration capacity of a household refrigerator may be round about __________ tons.

A. 0.15
B. 1.5
C. 4.5
D. 6.5

View Answer

Question 336

Gibbs free energy per mole for a pure substance is equal to the

A. Latent heat of vaporisation
B. Chemical potential
C. Molal boiling point
D. Heat capacity

View Answer

Question 337

Which of the following will increase the volume of a real gas by four times ?

A. Doubling the absolute temperature as well as pressure of the gas
B. Reducing pressure to one fourth at constant temperature
C. Reducing temperature to one fourth at constant pressure
D. Reducing the temperature to half and doubling the pressure

View Answer

Question 338

A solid is transformed into vapour without going to the liquid phase at

A. Triple point
B. Boiling point
C. Below triple point
D. Always

View Answer

Question 339

In the equation, PVn = constant, if the value of n = ± ∞, then it represents a reversible __________ process.

A. Adiabatic
B. Isometric
C. Isentropic
D. Isothermal

View Answer

Question 340

In an adiabatic process, the

A. Heat transfer is zero
B. Temperature change is zero
C. Work done is a path function
D. Enthalpy remains constant

View Answer

Question 341

y = specific heat ratio of an ideal gas is equal to

A. Cp/Cv
B. Cp/(CP-R)
C. 1 + (R/CV)
D. All of the above

View Answer

Question 342

Joule-Thomson co-efficient for a perfect gas is

A. Zero
B. Positive
C. Negative
D. None of these

View Answer

Question 343

Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants)

A. (atm)Δx, when Δx is negative
B. (atm)Δx, when Δx is positive
C. Dimensionless, when Δx = 0
D. (atm)Δx2, when Δx > 0

View Answer

Question 344

Pick out the correct statement.

A. Entropy and enthalpy are path functions
B. In a closed system, the energy can be exchanged with the surrounding, while. matter can not be exchanged
C. All the natural processes are reversible in nature
D. Work is a state function

View Answer

Question 345

A system is said to be at equilibrium, if the entropy of the system has reached __________ value.

A. Minimum
B. Zero
C. Maximum
D. None of these

View Answer

Question 346

The equation, Cp - Cv = R, is true for __________ gas.

A. No
B. Any real
C. Only ideal
D. Both B and C

View Answer

Question 347

Which of the following has the minimum value of COP for a given refrigeration effect?

A. Reverse Carnot cycle
B. Ordinary vapour-compression cycle
C. Vapour-compression process with a reversible expansion engine
D. Air refrigeration cycle

View Answer

Question 348

Consider the reaction, C + O₂ ⇋ CO₂ ;ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO₂ → C + O₂?

A. -94 kcal
B. + 94 kcal
C. > 94 kcal
D. < -94 kcal

View Answer

Question 349

__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.

A. Bucket
B. Throttling
C. Separating
D. A combination of separating & throttling

View Answer

Question 350

Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.

A. Gibbs-Duhem
B. Maxwell's
C. Clayperon
D. None of these

View Answer

Question 351

Specific __________ does not change during phase change at constant temperature and pressure.

A. Entropy
B. Gibbs energy
C. Internal energy
D. Enthalpy

View Answer

Question 352

Claude's liquefaction process employs the cooling of gases by

A. Expansion in an engine
B. Following a constant pressure cycle
C. Throttling
D. None of these

View Answer

Question 353

What is the ratio of adiabatic compressibility to isothermal compressibility?

A. 1
B. < 1
C. > 1
D. >> 1

View Answer

Question 354

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the

A. Low pressure and high temperature
B. Low pressure and low temperature
C. High pressure and low temperature
D. High pressure and high temperature

View Answer

Question 355

The internal energy of an incompressible fluid depends upon its

A. Pressure
B. Temperature
C. Both A & B
D. Neither A nor B

View Answer

Question 356

A refrigerator works on the principle of __________ law of thermodynamics.

A. Zeroth
B. First
C. Second
D. Third

View Answer

Question 357

Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour.

A. Superheated
B. Desuperheated
C. Non-condensable
D. None of these

View Answer

Question 358

With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure

A. Increases
B. Decreases
C. Remains same
D. Decreases linearly

View Answer

Question 359

Pick out the correct statement.

A. If an insoluble gas is passed through a volatile liquid placed in a perfectly insulated container, the temperature of the liquid will increase
B. A process is irreversible as long as Δ S for the system is greater than zero
C. The mechanical work done by a system is always equal to ∫P.dV
D. The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants

View Answer

Question 360

A Carnot cycle consists of the following steps :

A. Two isothermals and two isentropics
B. Two isobarics and two isothermals
C. Two isochorics and two isobarics
D. Two isothermals and two isochorics

View Answer

Question 361

Heat is added at constant pressure in an ideal __________ cycle.

A. Stirling
B. Brayton
C. Rankine
D. Both B and C

View Answer

Question 362

Specific heat of a gas for a reversible adiabatic process is

A. Negative
B. Zero
C. Infinity
D. None of these

View Answer

Question 363

Which of the following is affected by the temperature?

A. Fugacity
B. Activity co-efficient
C. Free energy
D. All of the above

View Answer

Question 364

In the reaction, H₂ +I₂ ⇋ 2HI, addition of an inert gas will

A. Increase the partial pressure of H₂
B. Increase the partial pressure of I₂
C. Increase the total pressure and hence shift the equilibrium towards the right
D. Not effect the equilibrium conditions

View Answer

Question 365

The absolute entropy for all crystalline substances at absolute zero temperature is

A. Zero
B. Negative
C. More than zero
D. Indeterminate

View Answer

Question 366

What happens in a reversible adiabatic compression?

A. Heating occurs
B. Cooling occurs
C. Pressure is constant
D. Temperature is constant

View Answer

Question 367

Which of the following equations is used for the prediction of activity co-efficient from experiments?

A. Van Laar equation
B. Margules equation
C. Wilson's equation
D. All of the above

View Answer

Question 368

For any system, what is the minimum number of degrees of freedom?

A. 1
B. 0
C. 2
D. 3

View Answer

Question 369

At absolute zero temperature, all substances have the same

A. Heat capacity
B. Crystalline structure
C. Entropy
D. None of these

View Answer

Question 370

Fundamental principle of refrigeration is based on the __________ law of thermodynamics.

A. zeroth
B. first
C. second
D. third

View Answer

Question 371

The necessary and sufficient condition for equilibrium between two phases is

A. The concentration of each component should be same in the two phases
B. The temperature of each phase should be same
C. The pressure should be same in the two phases
D. The chemical potential of each component should be same in the two phases

View Answer

Question 372

For a spontaneous process, free energy

A. is zero
B. increases
C. decreases whereas the entropy increases
D. and entropy both decrease

View Answer

Question 373

Ideal refrigeration cycle is

A. Same as Carnot cycle
B. Same as reverse Carnot cycle
C. Dependent on the refrigerant's properties
D. The least efficient of all refrigeration processes

View Answer

Question 374

Fugacity and pressure are numerically equal, when the gas is

A. In standard state
B. At high pressure
C. At low temperature
D. In ideal state

View Answer

Question 375

__________ increases with increase in pressure.

A. The melting point of wax
B. The boiling point of a liquid
C. both (a) and (b)
D. neither (a) nor (b)

View Answer

Question 376

Which of the following is not an extensive property?

A. Free energy
B. Entropy
C. Refractive index
D. None of these

View Answer

Question 377

Entropy, which is a measure of the disorder of a system is

A. Independent of pressure
B. Independent of temperature
C. Zero at absolute zero temperature for a perfect crystalline substance
D. All of the above

View Answer

Question 378

The number of degrees of freedom at the triple point of water is

A. 0
B. 1
C. 2
D. 3

View Answer

Question 379

Throttling process is a/an __________ process.

A. Reversible and isothermal
B. Irreversible and constant enthalpy
C. Reversible and constant entropy
D. Reversible and constant enthalpy

View Answer

Question 380

Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of

A. Sublimation
B. Fusion
C. Transition
D. Vaporisation

View Answer

Question 381

Which is not constant for an ideal gas?

A. (∂P/∂V)T
B. (∂V/∂T)P
C. (∂P/∂V)V
D. All of the above

View Answer

Question 382

Pick out the wrong statement.

A. Cp of monoatomic gases such as metallic vapor is about 5 kcal/kg. atom
B. The heat capacity of solid inorganic substance is exactly equal to the heat capacity of the substance in the molten state
C. There is an increase in entropy, when a spontaneous change occurs in an isolated system
D. At absolute zero temperature, the heat capacity for many pure crystalline substances is zero

View Answer

Question 383

Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.

A. Decreases
B. Increases
C. Remains constant
D. Decreases logarithmically

View Answer

Question 384

Refrigeration cycle

A. Violates second law of thermodynamics
B. Involves transfer of heat from low temperature to high temperature
C. Both A and B
D. Neither A nor B

View Answer

Question 385

Co-efficient of performance for a reversed Carnot cycle working between temperatures T₁ and T₂ (T₁ > T₂) is

A. T₂/(T₁ - T₂)
B. T₁/(T₁ - T₂)
C. (T₁ - T₂)/T₁
D. (T₁ - T₂)/T₂

View Answer

Question 386

For an exothremic reaction

A. Only enthalpy change (ΔH) is negative
B. Only internal energy change (ΔE) is negative
C. Both ΔH and ΔE are negative
D. Enthalpy change is zero

View Answer

Question 387

Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?

A. Freon
B. Liquid sulphur dioxide
C. Methyl chloride
D. Ammonia

View Answer

Question 388

All gases during throttling process at atmospheric temperature and pressure show a cooling effect except

A. CO2
B. H2
C. O2
D. N2

View Answer

Question 389

The equation Tds = dE - PdV applies to

A. Single phase fluid of varying composition
B. Single phase fluid of constant composition
C. Open as well as closed systems
D. Both B and C

View Answer

Question 390

Partial molar free energy of an element A in solution is same as its

A. Chemical potential
B. Activity
C. Fugacity
D. Activity co-efficient

View Answer

Question 391

Mollier chart is a __________ plot.

A. Pressure vs enthalpy
B. Pressure vs volume
C. Enthalpy vs entropy
D. Temperature vs entropy

View Answer

Question 392

In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.

A. Isothermal
B. Isobaric
C. Polytropic
D. Adiabatic

View Answer

Question 393

The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n- octane into pure compounds each at 1 atm is

A. -2 RT ln 0.5
B. -RT ln 0.5
C. 0.5 RT
D. 2 RT

View Answer

Question 394

For an incompressible fluid, the __________ is a function of both pressure as well as temperature.

A. Internal energy
B. Enthalpy
C. Entropy
D. All of the above

View Answer

Question 395

When a system is in equilibrium for all possible processes, the differential or finite change of entropy is

A. < 0
B. > 0
C. 0
D. None of these

View Answer

Question 396

Which of the following processes can not be made reversible even under ideal condition of operation?

A. Free expansion of a gas
B. Compression of air in a compressor
C. Expansion of steam in a turbine
D. All of the above

View Answer

Question 397

Specific volume of an ideal gas is

A. Equal to its density
B. The reciprocal of its density
C. Proportional to pressure
D. None of these

View Answer

Question 398

Internal energy is equal to the heat absorbed in case of a/an __________ process.

A. Constant volume
B. Polytropic
C. Adiabatic
D. Constant pressure

View Answer

Question 399

"The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture". This is

A. The statement as per Gibbs-Helmholtz
B. Called Lewis-Randall rule
C. Henry's law
D. None of these

View Answer

Question 400

Pick out the wrong statement.

A. Minimum number of degree of freedom of a system is zero
B. Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4
C. For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4
D. Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation

View Answer

Question 401

A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg⁻¹. K⁻¹. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg⁻¹ , K⁻¹ is

A. -1.87
B. 0
C. 1.26
D. 3.91

View Answer

Question 402

The variation of heat of reaction with temperature at constant pressure is given by the __________ law.

A. Kelvin's
B. Antonie's
C. Kirchoffs
D. None of these

View Answer

Question 403

Pick out the correct statement.

A. The available energy in an isolated system for all irreversible (real) processes decreases
B. The efficiency of a Carnot engine increases, if the sink temperature is decreased
C. The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy
D. All of the above

View Answer

Question 404

Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?

A. DE = Tds - PdV
B. DQ = CvdT + PdV
C. DQ = CpdT + Vdp
D. Tds = dE - PdV

View Answer

Question 405

The accentric factor of a materical, 'ω', is defined as ω = -log10(Prsat)Tr⁻¹ = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always

A. > 2
B. < 1
C. > 1
D. < 3

View Answer

Question 406

Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of

A. Fusion
B. Vaporisation
C. Transition
D. None of these

View Answer

Question 407

At __________ point, all the three phases (i.e.solid, liquid and gas) co-exist.

A. Eutcetic
B. Triple
C. Plait
D. Critical

View Answer

Question 408

With increase in compression ratio, the efficiency of the otto engine

A. Increases
B. Decreases
C. Remains constant
D. Increases linearly

View Answer

Question 409

One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is

A. 30554
B. 10373
C. 4988.4
D. 4364.9

View Answer

Question 410

If heat contents of CH₄, C₂H₄ and C₃H₈ are -17.9, 12.5 and -24.8 kcal/mole respectively, than ΔH for the reaction CH₄(g) + C₂H₄(g) ⇋ C₃H₈(g) will be __________ Kcal.

A. -19.4
B. -30.2
C. 55.2
D. -55.2

View Answer

Question 411

Which of the following is not a reversible process ?

A. Expansion of an ideal gas against constant pressure
B. Atmospheric pressure vaporisation of water at 100°C
C. Solution of NaCl in water at 50°C
D. None of these

View Answer

Question 412

Number of degrees of freedom for a three phase system in equilibrium comprising of three non-reacting chemical species is

A. 2
B. 0
C. 1
D. 3

View Answer

Question 413

All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.

A. Oxygen
B. Nitrogen
C. Air
D. Hydrogen

View Answer

Question 414

All gases during throttling process at atmospheric temperature and pressure show a cooling effect except

A. CO₂
B. H₂
C. O₂
D. N₂

View Answer

Question 415

"Law of corresponding states" says that

A. , two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
B. the surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature.
C. no gas can be liquified above the critical temperature, howsoever high the pressure may be.
D. the molar heat of energy of gas at constant volume should be nearly constant (about 3 calories).

View Answer

Question 416

In the reaction, C + O₂ → CO₂ ; ΔH = - 94 kcal. What is the heat content (enthalpy)of O₂?

A. -94 kcal
B. > -94 kcal
C. < - 94 kcal
D. Zero

View Answer

Question 417

__________ decreases during adiabatic throttling of a perfect gas.

A. Entropy
B. Temperature
C. Enthalpy
D. Pressure

View Answer

Question 418

In Joule-Thomson porous plug experiment, the

A. Enthalpy does not remain constant
B. Entire apparatus is exposed to surroundings
C. Temperature remains constant
D. None of these

View Answer

Question 419

Number of phases in a colloidal system are

A. 1
B. 2
C. 3
D. 4

View Answer

Question 420

Which of the following is not an intensive property?

A. Chemical potential
B. Surface tension
C. Heat capacity
D. None of these

View Answer

Question 421

If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is __________ law.

A. Hess's
B. Kirchoff's
C. Lavoisier and Laplace
D. None of these

View Answer

Question 422

Compressibility factor (i.e., the ratio of actual volume of gas to the volume predicted by ideal gas law) for all gases are

A. Always greater than one
B. Same at the same reduced temperature
C. Same at the same reduced pressure
D. Both B & C

View Answer

Question 423

For a constant volume process

A. dE = CpdT
B. dE = CvdT
C. dQ = dE + pdV
D. dW = pdV

View Answer

Question 424

Which one is true for a throttling process?

A. A gas may have more than one inversion temperatures
B. The inversion temperature is different for different gases
C. The inversion temperature is same for all gases
D. The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity

View Answer

Question 425

The expression, nCv(T₂ - T₁), is for the __________ of an ideal gas.

A. Work done under adiabatic condition
B. Co-efficient of thermal expansion
C. Compressibility
D. None of these

View Answer

Question 426

Work done in an adiabatic process between two states depends on the

A. Rate of heat transmission
B. Initial state only
C. End states only
D. None of these

View Answer

Question 427

Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas )

A. T
B. √T
C. T²
D. 1/√T

View Answer

Question 428

Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.

A. Equilibrium
B. Adiabatic
C. Steady
D. Unsteady

View Answer

Question 429

The adiabatic throttling process of a perfect gas is one of constant enthalpy

A. In which there is a temperature drop
B. Which is exemplified by a non-steady flow expansion
C. Which can be performed in a pipe with a constriction
D. In which there is an increase in temperature

View Answer

Question 430

A gas can be liquified by pressure alone only, when its temperature is __________ its critical temperature.

A. Less than
B. More than
C. Equal to or higher than
D. Less than or equal to

View Answer

Question 431

Pick out the wrong statement.

A. System (of partially miscible liquid pairs), in which the mutual solubility increases with rise in temperature, are said to possess an upper consolute temperature
B. Systems, in which the mutual solubility increases with decrease in temperature, are said to possess lower consolute temperature
C. Nicotine-water system shows both an upper as well as a lower consolute temperature, implying that they are partially miscible between these two limiting temperatures
D. None of these

View Answer

Question 432

The main feature of Carnot refrigeration cycle is that, it

A. Does not need the addition of external work for its functioning
B. Transfers heat from high temperature to low temperature
C. Accomplishes the reverse effect of the heat engine
D. None of these

View Answer

Question 433

The principle applied in liquefaction of gases is

A. Adiabatic expansion
B. Joule-Thomson effect
C. Both A and B
D. Neither A nor B

View Answer

Question 434

Enthalpy of a gas depends upon its

A. Temperature
B. Mass
C. Volume
D. Pressure

View Answer

Question 435

As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is

A. Not changed
B. Decreasing
C. Increasing
D. Data sufficient, can't be predicted

View Answer

Question 436

Critical solution temperature (or the con-solute temperature) for partially miscible liquids (e.g., phenol-water) is the minimum temperature at which

A. A homogeneous solution (say of phenol water) is formed
B. Mutual solubility of the two liquids shows a decreasing trend
C. Two liquids are completely separated into two layers
D. None of these

View Answer

Question 437

Boyle's law for gases states that

A. P ∝ 1/V, when temperature is constant
B. P ∝ 1/V, when temperature & mass of the gas remain constant
C. P ∝ V, at constant temperature & mass of the gas
D. P/V = constant, for any gas

View Answer

Question 438

In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respetively, the Carnot COP will be

A. 5.2
B. 6.2
C. 0.168
D. Data insufficient, can't be found out

View Answer

Question 439

If an ideal solution is formed by mixing two pure liquids in any proportion, then the __________ of mixing is zero.

A. Enthalpy
B. Volume
C. Both A & B
D. Neither A nor B

View Answer

Question 440

Standard temperature and pressure (S.T.P.) is

A. 0°C and 750 mm Hg
B. 15°C and 750 mm Hg
C. 0°C and 1 kgf/cm²
D. 15°C and 1 kgf/cm²

View Answer

Question 441

Forward reaction will be favoured for the exothermic reaction, represented by CO + H₂O ⇋ CO₂ + H₂, by

A. Low temperature and high pressure
B. Low temperature and low pressure
C. High temperature and high pressure
D. High temperature and low pressure

View Answer

Question 442

The fusion of a crystalline solid at its melting point to form a liquid at the same temperature is accompanied by

A. Decrease in enthalpy corresponding to evolution of heat
B. Decrease of entropy
C. Increase in enthalpy corresponding to absorption of heat
D. No change in enthalpy

View Answer

Question 443

What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor?

A. 2
B. 0
C. 3
D. 1

View Answer

Question 444

In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )

A. Addition of inert gas favours the forward reaction, when Δx is positive
B. Pressure has no effect on equilibrium, when Δn = 0
C. Addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero)
D. All of the above

View Answer

Question 445

The partial molar enthalpy of a component in an ideal binary gas mixture of composition Z, at a temperature T and pressure P, is a function only of

A. T
B. T and P
C. T, P and Z
D. T and Z

View Answer

Question 446

In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.

A. Isothermal
B. Adiabatic
C. Isentropic
D. Polytropic

View Answer

Question 447

Degree of freedom of a system consisting of a gaseous mixture of H₂ and NH₃ will be

A. 0
B. 1
C. 2
D. 3

View Answer

Question 448

Entropy of an ideal gas depends upon its

A. Pressure
B. Temperature
C. Both A & B
D. Neither A nor B

View Answer

Question 449

Pick out the wrong statement.

A. The chemical potential of a pure substance depends upon the temperature and pressure
B. The chemical potential of a component in a system is directly proportional to the escaping tendency of that component
C. The chemical potential of ith species (μi) in an ideal gas mixture approaches zero as the pressure or mole fraction (xi) tends to be zero at constant temperature
D. None of these

View Answer

Question 450

The enthalpy change when ammonia gas is dissolved in water is called the heat of

A. Solution
B. Formation
C. Dilution
D. Combustion

View Answer

Question 451

The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.

A. contracts
B. expands
C. does not change in volume
D. either (a), (b) or (c)

View Answer

Question 452

On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)S and the slope of the reversible isothermal line (∂P/∂V)T are related as (where, y = Cp/Cv) )

A. (∂P/∂V)S = (∂P/∂V)T
B. (∂P/∂V)S = [(∂P/∂V)T]Y
C. (∂P/∂V)S = y(∂P/∂V)T
D. (∂P/∂V)S = 1/y(∂P/∂V)T

View Answer

Question 453

1m³ of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be

A. 35 K
B. 174 K
C. 274 K
D. 154 K

View Answer

Question 454

During Joule-Thomson expansion of gases

A. enthalpy remains constant.
B. entropy remains constant.
C. temperature remains constant.
D. none of these.

View Answer

Question 455

If two gases have same reduced temperature and reduced pressure, then they will have the same

A. Volume
B. Mass
C. Critical temperature
D. None of these

View Answer

Question 456

Dryness fraction of wet steam is defined as the ratio of mass of vapour in the mixture to the mass of mixture __________ calorimeter is not used for measuring the dryness fraction of steam.

A. Bomb
B. Separating
C. Bucket
D. Throttling

View Answer

Question 457

Ideal gas law is applicable at

A. Low T, low P
B. High T, high P
C. Low T, high P
D. High T, low P

View Answer

Question 458

COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about

A. 0.5
B. 3.5
C. 4.5
D. 8.5

View Answer

Question 459

Second law of thermodynamics is concerned with the

A. Amount of energy transferred
B. Direction of energy transfer
C. Irreversible processes only
D. Non-cyclic processes only

View Answer

Question 460

The unit of fugacity is the same as that of the

A. Pressure
B. Temperature
C. Volume
D. Molar concentration

View Answer

Question 461

Pick out the wrong statement.

A. At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature
B. Normally, the gases which are easily liquified, are more soluble in common solvents
C. The gases which are capable of forming ions in aqueous solution, are much more soluble in water than in other solvents
D. At constant pressure, solubility of a gas in a liquid increases with rise in temperature

View Answer

Question 462

First law of thermodynamics is mathematically stated as

A. dQ = dE + dW
B. dQ = dE - dW
C. dE = dQ + dW
D. dW = dQ + dE

View Answer

Question 463

The value of gas constant 'R' is

A. 1.987 cal/gm mole °K
B. 1.987 BTU/lb. mole °R
C. Both A and B
D. Neither A nor B

View Answer

Question 464

For multicomponent multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases.

A. Chemical potential
B. Fugacity
C. Both A and B
D. Neither A nor B

View Answer

Question 465

The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is

A. R loge 4
B. R log10 4
C. Cv log10 4
D. Cv loge 4

View Answer

Question 466

An isolated system can exchange __________ with its surroundings.

A. Matter
B. Energy
C. Neither matter nor energy
D. Both matter and energy

View Answer

Question 467

An ideal liquid refrigerant should

A. Not have a subatmospheric vapour pressure at the temperature in the refrigerator coils
B. Not have unduly high vapour pressure at the condenser temperature
C. Both A and B
D. Have low specific heat

View Answer

Question 468

With increase in temperature, the atomic heat capacities of all solid elements

A. Increases
B. Decreases
C. Remains unchanged
D. Decreases linearly

View Answer

Question 469

Critical temperature is defined as the temperature above which a gas will

A. Not liquify (barring exceptions)
B. Immediately liquify
C. Never liquify however high the pressure may be
D. None of these

View Answer

Question 470

For an ideal solution, the value of activity co-efficient is

A. 0
B. 1
C. < 1
D. > 1

View Answer

Question 471

Pick out the correct equation relating 'F' and 'A'.

A. F = A + PV
B. F = E + A
C. F = A - TS
D. F = A + TS

View Answer

Question 472

When a gas is subjected to adiabatic expansion, it gets cooled due to

A. Decrease in velocity
B. Decrease in temperature
C. Decrease in kinetic energy
D. Energy spent in doing work

View Answer

Question 473

Which law of the thermodynamics provids basis for measuring the thermodynamic property?

A. First law
B. Zeroth law
C. Third law
D. Second law

View Answer

Question 474

For a multicomponent system, the term chemical potential is equivalent to the

A. Molal concentration difference
B. Molar free energy
C. Partial molar free energy
D. Molar free energy change

View Answer

Question 475

In a P-V diagram (for an ideal gas), an isothermal curve will coincide withan adiabatic curve (through a point), when

A. Cp < Cv
B. Cp = Cv
C. Cp > Cv
D. Cp ≥ Cv

View Answer

Question 476

In any spontaneous process, the __________ free energy decreases.

A. Helmholtz
B. Gibbs
C. Both A & B
D. Neither A nor B

View Answer

Question 477

Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system ?

A. Expansion valve
B. Condenser
C. Refrigerator
D. Compressor

View Answer

Question 478

Free energy change at equilibrium is

A. Zero
B. Positive
C. Negative
D. Indeterminate

View Answer

Question 479

Joule-Thomson co-efficient depends on the

A. Pressure
B. Temperature
C. Both A & B
D. Neither A nor B

View Answer

Question 480

Melting of wax is accompanied with __________ in entropy.

A. Increase
B. Decrease
C. No change
D. None of these

View Answer

Question 481

The four properties of a system viz. P, V, T, S are related by __________ equation.

A. Gibbs-Duhem
B. Gibbs-Helmholtz
C. Maxwell's
D. None of these

View Answer

Question 482

The number of degree of freedom for an azeotropic mixture of ethanol and water in vapour-liquid equilibrium, is

A. 3
B. 1
C. 2
D. 0

View Answer

Question 483

The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.

A. Gibbs-Duhem
B. Van Laar
C. Gibbs-Helmholtz
D. Margules

View Answer

Question 484

Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.

A. isothermal
B. adiabatic
C. isentropic
D. none of these

View Answer

Question 485

One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one

A. Hour
B. Day
C. Minute
D. Second

View Answer

Question 486

For an ideal gas, the chemical potential is given by

A. RT dlnP
B. R dlnP
C. R dlnf
D. None of these

View Answer

Question 487

Compressibility factor of a gas is

A. Not a function of its pressure
B. Not a function of its nature
C. Not a function of its temperature
D. Unity, if it follows PV = nRT

View Answer

Question 488

Work done is a

A. Property of the system
B. Path function
C. Point function
D. State description of a system

View Answer

Question 489

Trouton's ratio is given by (where λb, = molal heat of vaporisation of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, °K )

A. λb/Tb
B. Tb/λb
C. √(λb/Tb)
D. √(Tb/λb)

View Answer

Question 490

PVγ = Constant (where, γ = Cp/Cv) is valid for a/an __________ process.

A. Isothermal
B. Isentropic
C. Isobaric
D. Adiabatic

View Answer

Question 491

What is the degree of freedom for two mis-cible (non-reacting) substances in vapor-liquid equilibrium forming an azeotrope?

A. 0
B. 1
C. 2
D. 3

View Answer

Question 492

__________ equation predicts the activity co-efficient from experimental data.

A. Lewis-Randall
B. Margules
C. Van Laar
D. Both B & C

View Answer

Question 493

Chemical potential is a/an

A. Extensive property
B. Intensive property
C. Force which drives the chemical system to equilibrium
D. Both B and C

View Answer

Question 494

When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change. This is called the

A. Le-Chatelier principle
B. Kopp's rule
C. Law of corresponding state
D. Arrehenius hypothesis

View Answer

Question 495

For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm³ and that in vapour phase in 391.1 cm³.Fugacity of water (in kPa) at 9000 kPa will be

A. 6738.9
B. 6753.5
C. 7058.3
D. 9000

View Answer

Question 496

As the temperature is lowered towards the absolute zero, the value of ∂(ΔF)/∂T, then approaches

A. Unity
B. Zero
C. That of the heat of reaction
D. Infinity

View Answer

Question 497

For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases.

A. decreases
B. increases
C. remains same
D. decreases linearly

View Answer

Question 498

At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is

A. Zero
B. One
C. Infinity
D. Negative

View Answer

Question 499

Pick out the wrong statement:

A. The expansion of a gas in vacuum is an irreversible process
B. An isometric process is a constant pressure process
C. Entropy change for a reversible adiabatic process is zero
D. Free energy change for a spontaneous process is negative

View Answer

Question 500

Out of the following refrigeration cycles, which one has maximum COP?

A. Air cycle
B. Carnot cycle
C. Ordinary vapor compression cycle
D. Vapor compression with a reversible expansion engine

View Answer

Question 501

The unit of equilibrium constant of a chemical reaction is the same as that of

A. Molar concentration
B. Temperature
C. Internal energy
D. None of these

View Answer

Question 502

Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.

A. Reaction mechanism
B. Calculation of rates
C. Energy transformation from one form to the another
D. None of these

View Answer

Question 503

Extensive properties of a thermodynamic system depend upon the __________ of the system.

A. Specific volume
B. Temperature
C. Mass
D. Pressure

View Answer

Question 504

The free energy change for a chemical reaction is given by (where, K = equilibrium constant)

A. RT lnK
B. -RT lnK
C. -R lnK
D. T lnK

View Answer

Question 505

When a gas in a vessel expands, its internal energy decreases. The process involved is

A. Reversible
B. Irreversible
C. Isothermal
D. Adiabatic

View Answer

Question 506

What happens in a reversible adiabatic expansion process?

A. Heating takes place
B. Cooling takes place
C. Pressure is constant
D. Temperature is constant

View Answer

Question 507

Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the

A. Two temperatures only
B. Pressure of working fluid
C. Mass of the working fluid
D. Mass and pressure both of the working fluid

View Answer

Question 508

Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.

A. Less than
B. Same as
C. More than
D. Half

View Answer

Question 509

The number of degrees of freedom for a mixture of ice and water (liquid) are

A. 2
B. 3
C. 1
D. 0

View Answer

Question 510

Entropy change for an irreversible isolated system is

A. ∞
B. 0
C. < 0
D. > 0

View Answer

Question 511

The second law of thermodynamics states that

A. The energy change of a system undergoing any reversible process is zero
B. It is not possible to transfer heat from a lower temperature to a higher temperature
C. The total energy of system and surrounding remains the same
D. None of the above

View Answer

Question 512

Gibbs free energy of mixing at constant pressure and temperature is always

A. 0
B. ∞
C. + ve
D. - ve

View Answer

Question 513

For equilibrium process (i.e. reversible) in an isolated system

A. ds = 0
B. ds < 0
C. ds > 0
D. ds = Constant

View Answer

Question 514

There is a change in __________ during the phase transition.

A. Volume
B. Pressure
C. Temperature
D. All of the above

View Answer

Question 515

Pick out the wrong statement.

A. Trouton's ratio of non-polar liquids is calculated using Kistyakowasky equation
B. Thermal efficiency of a Carnot engine is always less than 1
C. An equation relating pressure, volume and temperature of a gas is called ideal gas equation
D. None of these

View Answer

Question 516

Pick out the wrong statement.

A. Activity co-efficient is dimensionless.
B. In case of an ideal gas, the fagacity is equal to its pressure.
C. In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.
D. The fugacity co-efficient is zero for an ideal gas.

View Answer

Question 517

For a single component two phase mixture, the number of independent variable properties are

A. Two
B. One
C. Zero
D. Three

View Answer

Question 518

Which of the following behaves most closely like an ideal gas?

A. He
B. N₂
C. O₂
D. H₂

View Answer

Question 519

Pick out the wrong statement.

A. Enthalpies of all elements in their standard states are assumed to be zero
B. Combustion reactions are never en-dothermic in nature
C. Heat of reaction at constant volume is equal to the change in internal energy
D. Claussius-clayperon equation is not applicable to melting process

View Answer

Question 520

Fugacity and pressure are numerically not equal for the gases

A. At low temperature and high pressure
B. At standard state
C. Both A and B
D. In ideal state

View Answer

Question 521

For a constant pressure reversible process, the enthalpy change (ΔH) of the system is

A. Cv.dT
B. Cp.dT
C. ∫Cp.dT
D. ∫Cv.dT

View Answer

Question 522

What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?

A. 0
B. 1
C. 2
D. 3

View Answer

Question 523

__________ explains the equilibrium constant for any chemical reaction.

A. Henry's law
B. Law of mass action
C. Hess's law
D. None of these

View Answer

Question 524

The third law of thermodynamics states that the

A. Heat capacity of a crystalline solid is zero at absolute zero temperature
B. Heat transfer from low temperature to high temperature source is not possible without external work
C. Gases having same reduced properties behave similarly
D. None of these

View Answer

Question 525

Pick out the correct statement.

A. Compression ratio of an Otto engine is comparatively higher than a diesel engine
B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio
C. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat
D. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

View Answer

Question 526

High pressure steam is expanded adiabati-cally and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process:

A. Δ H = 0 and ΔS = 0
B. Δ H ≠ 0 and ΔS = 0
C. Δ H ≠ 0 and ΔS ≠ 0
D. Δ H = 0 and ΔS ≠ 0

View Answer