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Chemical Reaction Engineering MCQ Questions & Answers

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




Question 1

Design of heterogeous catalytic reactor involves consideration of __________ steps.

A. Only chemical
B. Only physical
C. Both A & B
D. Neither A nor B

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Question 2

Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the

A. Activation energy
B. Equilibrium constant
C. Heat of reaction
D. None of these

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Question 3

In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same.

A. Semi-batch
B. Tubular
C. Batch
D. Back-mix

View Answer

Question 4

The heat of reaction

A. Depends on the pressure only
B. Depends on the mechanism of reaction only
C. Depends on both pressure and mechanism of reaction
D. Is independent of the mechanism of reaction

View Answer

Question 5

Pick out the correct statement.

A. A chemical reaction accompanied by absorption of heat is called an exothermic reaction
B. A chemical reaction accompanied by evolution of heat is called an endother-mic reaction
C. The rate constant for a first order reaction does not change on changing the concentration units
D. Chemical equilibrium state is dynamic in nature

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Question 6

For a __________ order reaction, the units of rate constant and rate of reaction are the same.

A. Zero
B. First
C. Second
D. Fractional

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Question 7

The reactions of high molecularity are rare, because

A. Of very large activation energy of many bodies
B. Of low probability of many body collisions
C. Many body collisions are not favoured energetically
D. Of requirement of very large concentration for such reactions

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Question 8

In a chemical reaction, __________ are conserved.

A. Ions
B. Masses
C. Atoms
D. Both B & C

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Question 9

Which of the following is the most suitable for isothermal operation?

A. Batch reactor
B. Back-mix reactor
C. Plug-flow reactor
D. Fixed bed reactor

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Question 10

Pick out the correct statement.

A. In catalytic reactions, the catalyst reacts with the reactants
B. A catalyst initiates a chemical reaction
C. A catalyst lowers the activation energy of the reacting molecules
D. A catalyst can not be recovered chemi cally unchanged at the end of the chemical reaction

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Question 11

The rate of reaction does not decrease appreciably as the reaction proceeds in case of __________ reactions.

A. Autocatalytic
B. Exothermic
C. Endothermic
D. Autothermal

View Answer

Question 12

Which of the following is not endothermic in nature?

A. Combustion of sulphur
B. Gasification of carbon
C. Thermal cracking of fuel oil
D. Steam reforming of naphtha

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Question 13

In an exothermic reaction, the energy of the reacting substances as compared to that of products is

A. More
B. Less
C. Same
D. Either A or B, depends on order of reaction

View Answer

Question 14

From among the following, choose one which is not an exothermic process.

A. Methanol synthesis
B. Catalytic cracking
C. Ammonia synthesis
D. Oxidation of sulphur

View Answer

Question 15

For identical flow rate and feed composition, X plug flow reactors (PER) in series with a total volume V gives the same conversion as single

A. CSTR of volume V
B. PFR of volume V
C. CSTR of volume V/X
D. PFR of volume V/X

View Answer

Question 16

A first order reaction A → B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A at the centre of the pellet is much less than at the external surface, the process is limited by

A. Diffusion within the pellet
B. Reaction
C. External mass transfer
D. None of the above

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Question 17

Molecularity of an elementary reaction, P + Q → R + S is

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

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Question 18

Carbon particles accummulated on the catalyst used in the gas oil cracking lies in the category of __________ poison.

A. Deposited
B. Chemisorbed
C. Selectivity
D. Stability

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Question 19

A catalyst in a chemical reaction

A. Decreases the activation energy
B. Alters the reaction mechanism
C. Increases the frequency of collisions of reacting species
D. All of the above

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Question 20

With an increase in pressure in gaseous phase chemical reactions, the fractional conversion __________ when the number of moles decreases.

A. Increases
B. Decreases
C. Remains unaffected
D. Unpredictable from the data

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Question 21

With decrease in temperature, the equilibrium conversion of a reversible endother-mic reaction

A. decreases
B. increases
C. remains unaffected
D. increases linearly with temperature

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Question 22

Considering the endotheomic dissociation of CaCO₃ in a closed vessel (CaCO₃ ⇋ CaO + CO₂), the pressure of CO₂ increases, if

A. A catalyst is added
B. The temperature is increased
C. An inert gas is pumped keeping the temperature constant
D. None of these

View Answer

Question 23

Brunaur, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume & the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation?

A. Langmuir
B. There is no dynamic equilibrium between successive layer
C. The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer (except the first one) is involved in each of the evaporation process
D. None of these

View Answer

Question 24

For reaction, P + 2 → 3R, molar rate of consumption of P is

A. Double of that of Q
B. Same as that of Q
C. Half of that of Q
D. 2/3rd of that of Q

View Answer

Question 25

From Arhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is

A. K cal
B. K cal/°K
C. °K
D. K cal. °K

View Answer

Question 26

The order of a chemical reaction is

A. An experimentally determined quantity
B. Always equal to the total stoichiometric number of reactants
C. Never fractional
D. None of these

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Question 27

A catalyst inhibitor

A. Lessens its selectivity
B. May be useful for suppressing undesirable side reactions
C. Is added in small quantity during the catalyst manufacture itself
D. All of the above

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Question 28

A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m³ and volumetric flow rate 1m³ /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m³ . The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 kmole/m³ , the volume of the mixed flow reactor should be increased by a factor of

A. 7
B. 6
C. 3
D. 7-3

View Answer

Question 29

Fractional conversion __________ for an exothermic reversible chemical reaction, when the temperature is maximum.

A. Increases
B. Remains unchanged
C. Decreases
D. Unpredictable from the data

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Question 30

For a first order reaction carried out in a plug flow reactor, the space time is

A. 1/K In C0/C
B. 1/K In C/C0
C. K In C0/C
D. K In C/C0

View Answer

Question 31

Fluidised bed reactor is characterised by

A. Uniformity of temperature
B. Comparatively smaller equipment
C. Very small pressure drop
D. Absence of continuous catalyst regeneration facility

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Question 32

An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction

A. Is maximum at the inlet of the reactor
B. Goes through a maximum along the length of the reactor
C. Goes through a minimum along the length of the reactor
D. Is maximum at the exit of the reactor

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Question 33

For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the __________ adsorption.

A. Physical
B. Chemical
C. Both A and B
D. Neither A nor B

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Question 34

Pick out the correct statement.

A. A catalyst does not change AH of the reaction
B. A catalyst changes the equilibrium point
C. Law of mass action was suggested by Le-Chatelier
D. The difference between the energy of reactants and that of the products is the activation energy

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Question 35

For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a __________ reactor.

A. Stirred tank
B. Tubular flow
C. Batch
D. Fixed bed

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Question 36

The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of __________ order.

A. Zero
B. First
C. Second
D. None of these

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Question 37

Participation of __________ is involved in the occurrence of a chemical reaction.

A. Protons
B. Neutrons
C. Electrons
D. None of these

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Question 38

Space time in flow reactor is

A. Usually equal to the residence time
B. The reciprocal of the space velocity
C. A measure of its capacity
D. Both A and B

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Question 39

Backmixing is most predominant in

A. A well stirred batch reactor
B. A plug-flow reactor
C. A single CSTR
D. CSTR's connected in series

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Question 40

A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to

A. Lose a proton
B. Gain a proton
C. Lose an electron
D. None of these

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Question 41

In flow reactors, the performance equations interrelate the rate of reaction to the

A. Feed rate
B. Reactor volume
C. Extent of reaction
D. All of the above

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Question 42

Specific rate constant for a second order reaction

A. is independent of temperature.
B. varies with temperature.
C. depends on the nature of the reactants.
D. both (b) and (c).

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Question 43

__________ resistance is not involved in the combustion of a carbon particle.

A. Gas film
B. Ash
C. Chemical reaction
D. None of these

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Question 44

Which of the following is used for calcination of limestone and dolomite in industrial practice?

A. Fluidised bed reactor
B. Moving bed reactor
C. Fixed bed reactor
D. None of these

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Question 45

A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length

A. decreases.
B. increases.
C. is at the highest allowable temperature throughout.
D. first increases and then decreases.

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Question 46

Radioactive decay follows __________ order kinetics.

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

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Question 47

The rate of the heterogenous catalytic reaction A(g) + B(g) ? C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction isA. absorption of A.

A. Absorption of A
B. Surface reaction between absorbed A and absorbed B
C. Surface reaction between absorbed A and B in the gas phase
D. Surface reaction between A in the gas phase and absorbed B

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Question 48

For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to l/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times.

A. 8
B. 16
C. 1-8
D. 1-16

View Answer

Question 49

For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of 'P' is doubled. If the reaction rate is proportional to Cpn, then what is the value of 'n' for this chemical reaction

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

View Answer

Question 50

Chemical kinetics can predict the __________ of a chemical reaction.

A. Rate
B. Feasibility
C. Both A & B
D. Neither A nor B

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Question 51

When a catalyst increases the rate of chemical reaction, the rate constant

A. Decreases
B. Increases
C. Remains constant
D. Becomes infinite

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Question 52

What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half life time of the reaction?

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

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Question 53

The irreversible reaction, X → Y, is the special case of the reversible reaction, X ⇋ Y, in which the

A. Equilibrium constant is infinite
B. Fractional conversion of
C. Concentration of
D. All of the above

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Question 54

Arhenious equation shows the variation of __________ with temperature.

A. Reaction rate
B. Rate constant
C. Energy of activation
D. Frequency factor

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Question 55

The excess energy of the reactants required to dissociate into products is known as the __________ energy.

A. Thermal
B. Activation
C. Threshold
D. Binding

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Question 56

A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction.

A. Less than
B. Equal to
C. More than
D. Equal to or more than

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Question 57

For a zero order chemical reaction, the

A. half life period is directly proportion to the initial concentration of the reac-tants.
B. plot of products concentration with time is a straight line through the origin.
C. products concentration increases linerarly with time.
D. all (a), (b) and (c).

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Question 58

In a zero order reaction, reactants concentration does not change with time and the

A. Time for half change is half the time taken for completion of the reaction
B. Time for half change is independent of the initial concentration
C. Time for completion of the reaction is independent of the initial concentration
D. Reaction rate is trebled when the initial concentration is trebled

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Question 59

The irreversible reaction is a special case of reversible reaction, if the

A. Equilibrium constant is 1
B. Conversion of the reactant at equilibrium condition is zero
C. Reactant concentration at equilibrium condition is zero
D. All of the above

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Question 60

Which of the following is an autocatalytic reaction?

A. Photochemical reactions
B. Microbial fermentation reaction
C. Enzyme fermentation reaction
D. Ammonia synthesis reaction

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Question 61

Radioactive decay follows __________ order kinetics.

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

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Question 62

For a heterogeneous catalytic reaction

A. Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction
B. A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important
C. The catalyst does not form an intermediate complex with the reactant
D. The surface of the catalyst does not play an important role during reaction

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Question 63

According to Arhenious equation of temperature dependency of rate constant for an elementary reaction

A. K ∝ √T
B. K ∝ e-E/RT
C. K ∝ T e-E/RT
D. None of these

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Question 64

When a catalyst increases the rate of forward reaction, the value of rate constant

A. Increases
B. Decreases
C. Remain same
D. Becomes infinite

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Question 65

A reaction which is catalysed by a base is catalysed by all substances which have a tendency to

A. Lose a proton
B. Gain a proton
C. Gain an electron
D. None of these

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Question 66

An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is

A. Maximum at the inlet of the reactor
B. Maximum at the exit of the reactor
C. Maximum at the centre of the reactor
D. Constant throughout the reactor

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Question 67

Given, 3H₂ + CO = CH₄ + H₂O, KP = 101.84 and, 4H₂ + CO₂ = CH₄ + 2H₂O, KP = 101.17the KP for the reaction CO + H₂O = CO₂ + H₂ is

A. 103.01
B. 10-0.67
C. 10-3.01
D. L00.67

View Answer

Question 68

What is the order of a chemical reaction whose rate is deter-mined by the variation of one concentration term only?

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

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Question 69

Pick out the wrong statement.

A. The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively.
B. Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant.
C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty.
D. In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in logitudinal direction.

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Question 70

The rate expression for a heterogenous catalytic reaction is given by, - rA = K.KA PA(1 + KA.PA + Kr.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A)

A. E
B. E + ΔHA
C. E + ΔHA - ΔHR
D. ΔHA + ΔHR

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Question 71

Velocity of a reaction depends upon the

A. Nature of the reactants
B. Concentration of the reactants
C. Temperature at which the reaction is carried
D. All of the above

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Question 72

In which of the following gaseous phase reversible reactions, the product yield can not be increased by the application of high pressure?

A. N₂ + O₂ ⇋ 2NO
B. PCl3 + Cl₂ ⇋ PCl5
C. N + 3H₂ ⇋ 2NH₃
D. 2SO₂ + O₂ ⇋ 2SO₃

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Question 73

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will

A. Remain the same
B. Be halved
C. Also be doubled
D. Become one fourth

View Answer

Question 74

Inversion of cane sugar is an example of

A. Unimolecular reaction with first order
B. Bimolecular reaction with second order
C. Bimolecular reaction with first order
D. Unimolecular reaction with second order

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Question 75

B.E.T. method of finding out surface area of a catalyst, uses the extension of __________ isotherm.

A. Langmuir
B. Freundlich
C. Tempkin
D. None of these

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Question 76

The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is

A. ∞
B. 0
C. 1
D. > 1

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Question 77

The concentration of A in a first order reaction, A → B, decreases

A. Linearly with time
B. Exponentially with time
C. Very abruptly towards the end of the reaction
D. Logarithmically with time

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Question 78

A catalyst

A. Initiates a reaction
B. Lowers the activation energy of reacting molecules
C. Is capable of reacting with any one of the reactants
D. Can not be recovered chemically unchanged at the end of a chemical reaction

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Question 79

The rate of a gas phase reaction is given by K . CA . CB. If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times.

A. 4
B. 16
C. 8
D. 2

View Answer

Question 80

Enzymes are destroyed, when the

A. Temperature is very high
B. Reactant's concentration is very high
C. Reactant's concentration is very low
D. Reaction rate is independent of the reactant's concentration

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Question 81

The experimentally determined overall order of the reaction, A + B → C + D, is two. Then the

A. Reaction is elementary with a molecularity of 2
B. Molecularity of the reaction is 2, but the reaction may not be elementary
C. Reaction may be elementary with molecularity of 2
D. Reaction is elementary but the molecularity may not be 2

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Question 82

6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO₂ and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant?

A. 100%
B. 95%
C. 75%
D. 20%

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Question 83

In a/an __________ vessel, the fluid enters and leaves following plug flow.

A. Open
B. Closed
C. Open-closed
D. Close-opened

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Question 84

For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the

A. Catalyst size is reduced or the catalyst diffusivity is reduced
B. Catalyst size is reduced or the catalyst diffusivity is increased
C. Catalyst size is increased or the catalyst diffusivity is reduced
D. Catalyst size is increased or the catalyst diffusivity is increased

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Question 85

In Langmuir treatment of adsorption,

A. Whole surface of the catalyst does not have the same activity for adsorption and there is attraction between the adsorbed molecule
B. Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site
C. All the adsorption does not take place by the same mechanism
D. Extent of adsorption is more than one complete monomolecular layer on the surface

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Question 86

Which of the following is not a dimension-less group used in catalysis ? (where, D = dispersion co-efficient, cm² /sec.D1 = diffusion co-efficient; cm²/sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm³/sec . V = volume, cm³.)

A. Reactor dispersion number (D/vL)
B. Reduced time (vt/V)
C. Thiele modulus (L√(k/D1)
D. None of these

View Answer

Question 87

Pick the WRONG design guideline for a reactor in which the reactions, A → R (desired) and A → S (undesired) are to take place. The ratio of the reaction rates is rR/rS = (k₁/k₂).Csub>Aa-b

A. Use high pressure and eliminate inerts, when a > b
B. Avoid recycle, when a > b
C. Use batch reactor or plug flow reactor, when a > b
D. Use CSTR with a high conversion, when a > b

View Answer

Question 88

The value of steric factor 'P' in the equation k = PZeE/RT usually ranges from

A. L.0 to 10⁻⁸
B. L.l.to 10²
C. 0.1 to 0.9
D. None of these

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Question 89

Sulphuric acid is used as a catalyst in the

A. hydrogenation of oils.
B. gas phase oxidation of SO2 in chamber process.
C. alkylation of hydrocarbons.
D. none of these.

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Question 90

The energy balance equation over a tubular reactor under transient conditions is

A. An ordinary non-linear differential equation
B. An algebric differential equation
C. A linear partial differential equation
D. A non-linear partial differential equation

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Question 91

An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4kmole/m³ of each A and B enters the reactor at 8m³ /hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed?(Data: Heat of reaction = - 50 kJ/mole, Density of the reacting mixture = 1000kg/m³, Specific heat of reacting mixture = 2kJ/kg.K)The above data can be assumed to be independent of temperature and composition.

A. 190
B. 290
C. 390
D. 490

View Answer

Question 92

Vegetable oils are hydrogenated in a __________ reactor.

A. Slurry
B. Plug flow
C. Homogeneous catalytic
D. None of these

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Question 93

A rise in temperature

A. Normally tends to increase the reaction rate
B. Does not affect a catalysed reaction
C. Does not affect photo-chemical reaction rates
D. All of the above

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Question 94

For any reaction, we may write conversion as a function of

A. Time
B. Temperature
C. Concentration
D. All of the above

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Question 95

Pick out the wrong statement pertaining to space velocity of flow reactors.

A. The unit of space velocity is (time)⁻¹
B. The space velocity of 3 hr⁻¹ means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour
C. The space velocity of 3 hr⁻¹ means that one third reactor volume of feed at specified conditions are being fed into the reactor
D. None of these

View Answer

Question 96

Space time equals the mean residence time

A. When the density of the reaction mixture is constant
B. For large diameter tubular reactor
C. For narrow diameter tubular reactor
D. For CSTR

View Answer

Question 97

What is the dispersion number for a plug flow reactor?

A. 0
B. ?
C. 1
D. -1

View Answer

Question 98

Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction.

A. Order
B. Overall order
C. Molecularity
D. None of these

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Question 99

An autothermal reactor is

A. Most suitable for a second order reaction
B. Most suitable for a reversible reaction
C. Completely self-supporting in its thermal energy requirements
D. Isothermal in nature

View Answer

Question 100

Bulk diffusion in catalyst pore __________ with increase in pressure.

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

View Answer

Question 101

Rate of a chemical reaction is not affected by the

A. Catalyst
B. Temperature
C. Reactant's concentration
D. Number of molecules of reactants taking part in the reaction

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Question 102

Which of the following factors control the deactivation of a porous catalyst pellet?

A. Decay reactions
B. Pore diffusion
C. Form of surface attack by poison
D. All of the above

View Answer

Question 103

Fluid flow in a real packed bed can be approximated as __________ model.

A. Plug flow
B. Dispersion
C. Mixed flow
D. Tank in series

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Question 104

The exit age distribution curve E(t) for an ideal CSTR with the average residence time, τ, is given by

A. E-t/τ
B. E-t/τ/T
C. 1 - e-t/τ
D. 1 - (e-t/τ/T)

View Answer

Question 105

'N' plug flow reactors in series with a total volume 'V' gives the same conversion as a single plug flow reactor of volume 'V' for __________ order reactions.

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

View Answer

Question 106

Rate constant 'k' and absolute temperature 'T' are related by collision theory (for bimolecular) as

A. k ∝ T1.5
B. k ∝ exp(-E/RT)
C. k ∝ √T
D. k ∝ T

View Answer

Question 107

The rate of a homogeneous reaction is a function of

A. Temperature and pressure only
B. Temperature and composition only
C. Pressure and composition only
D. All of the above

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Question 108

__________ catalytic reaction is involved in the thermal cracking of gas oil.

A. Homogeneous
B. Homogeneous non
C. Heterogeneous
D. Heterogeneous non

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Question 109

For a tubular reactor with space time 'τ' and residence time 'θ', the following statement holds good.

A. τ and θ are always equal
B. τ = θ , when the fluid density changes in the reactor
C. τ = θ , for an isothermic tubular reactor in which the density of the process fluid is constant
D. τ = θ , for a non-isothermal reactor

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Question 110

For a tubular flow reactor with uniform concentration and temperature, the independent variable is

A. Time
B. Length
C. Diameter
D. None of these

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Question 111

For the liquid phase parallel reactions:R, rR = K?.CA2; E? = 80 KJ/moleS, rS = K?.CA ; E? = 120 KJ/mole The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at

A. Low temperature in a CSTR
B. High temperature in a CSTR
C. Low temperature in a PFR
D. High temperature in a PFR

View Answer

Question 112

The reason why a catalyst increases the rate of reaction is that, it

A. decreases the energy barrier for reaction.
B. increases the activation energy.
C. decreases the molecular collision diameter.
D. none of these.

View Answer

Question 113

For the chemical reaction X → Y, it is observed that, on doubling the concentration of 'X', the reaction rate quadruples. If the reaction rate is proportional to Cxn, then what is the value of 'n' ?

A. 4
B. 1-4
C. 16
D. 2

View Answer

Question 114

The importance of diffusion in a catalyst are increased by

A. Large catalyst particle size
B. An active surface of the catalyst
C. Small pore diameter
D. All of the above

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Question 115

A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ?

A. Large reactor followed by smaller one
B. Smaller reactor followed by larger one
C. Either of the arrangement A or B will give the same yield
D. Data insufficient, can

View Answer

Question 116

The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a 'tanks in series model' comprising of 'm' tanks is equal to

A. m
B. 1/m
C. √m
D. m²

View Answer

Question 117

B.E.T. method can be used to determine the __________ of a porous catalyst.

A. Solid density
B. Pore volume
C. Surface area
D. All of the above

View Answer

Question 118

The energy of activation of a chemical reaction

A. Is same as heat of reaction at constant pressure
B. Is the minimum energy which the molecules must have before the reaction can take place
C. Varies as fifth power of the temperature
D. Both B and C

View Answer

Question 119

The temperature dependence of reaction rate constant (K) by Arhenius law is given by

A. K α e-E/RT
B. K α eE/RT
C. K α T . e-E/RT
D. K α √T . e-E/RT

View Answer

Question 120

The increase in the rate of reaction with temperature is due to

A. Increase in the number of effective collisions
B. Decrease in activation energy
C. Increase in the average kinetic energy of the reacting molecules
D. None of these

View Answer

Question 121

A batch reactor is

A. Suitable for gas-phase reactions on commercial scale
B. Suitable for liquid phase reactions involving small production rate
C. Least expensive to operate for a given rate
D. Most suitable for very large production rate

View Answer

Question 122

The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is

A. backmix reactor
B. plug flow reactor
C. series of CSTR
D. PFR in series

View Answer

Question 123

Which of the following is not a theory of homogeneous reaction?

A. Collision theory and activated complex theory
B. Chain reaction theory
C. Radiation hypothesis
D. None of these

View Answer

Question 124

Kinetics of a catalytic reaction can be best studied on a/an __________ reactor.

A. Mixed
B. Integral (plug flow)
C. Differential (flow)
D. Either A, B and C

View Answer

Question 125

The effect of increasing pressure on the gaseous equilibrium of the reaction 2X+3Y ⇋ 3X+2Y indicates that

A. Pressure has no effect
B. Backward reaction is favoured
C. Forward reaction is favoured
D. None of these

View Answer

Question 126

The increase in the rate of reaction with temperature is due to

A. increase in the number of effective collisions.
B. decrease in activation energy.
C. increase in the average kinetic energy of the reacting molecules.
D. none of these.

View Answer

Question 127

The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the

A. Space time for each parallel line is same
B. Space time for parallel lines is different
C. Larger reactors have more space time compared to smaller ones
D. None of these

View Answer

Question 128

The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst.

A. Increases
B. Decreases
C. Remains unaffected
D. Unpredictable from the data

View Answer

Question 129

A catalyst

A. initiates a reaction.
B. lowers the activation energy of reacting molecules.
C. is capable of reacting with any one of the reactants.
D. can not be recovered chemically unchanged at the end of a chemical reaction.

View Answer

Question 130

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant

A. Is independent of pressure
B. Increases with pressure
C. Decreases with pressure
D. Increases /decreases with pressure depending on the stoichiometric co-efficients of the reaction

View Answer

Question 131

Pick out the wrong statement.

A. Hold back' is defined as the fraction of material that stays longer than the mean residence time
B. Study of non-ideal flow reactor is done experimentally by stimulus-response technique
C. For studying a chemical reaction, it is desirable to monitor the reactants during initial stages and the products during the final stages of reaction
D. batch reactor can not be used to study the kinetics of catalytic reaction

View Answer

Question 132

Specific rate constant for a second order reaction

A. Is independent of temperature
B. Varies with temperature
C. Depends on the nature of the reactants
D. Both B and C

View Answer

Question 133

In a semi-batch reactor,

A. Mixing takes place in axial direction only
B. Velocity of reaction can be controlled
C. Condition similar to plug flow reactor exists
D. Residence time is constant

View Answer

Question 134

A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction.

A. Less than
B. Equal to
C. More than
D. Equal to or more than

View Answer

Question 135

__________ explains the mechanism of catalysis.

A. Activated complex theory
B. Collision theory
C. Thermodynamics
D. None of these

View Answer

Question 136

A reactor is generally termed as an autoclave, when it is a

A. high pressure batch reactor.
B. atmospheric pressure tank reactor.
C. high pressure tubular reactor.
D. atmospheric pressure CSTR.

View Answer

Question 137

The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of E/R is

A. 8987°K
B. 9210°K
C. 8764°K
D. 8621°K

View Answer

Question 138

For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor.

A. fixed
B. fluidised bed reactor followed by a fixed
C. fixed bed reactor followed by a fluidised
D. fluidised

View Answer

Question 139

With increase in temperature, the equilibrium __________ rises in case of endothermic reaction.

A. Constant
B. Conversion
C. Both A & B
D. Neither A nor B

View Answer

Question 140

A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be __________ minutes.

A. 4
B. 8
C. 12
D. 16

View Answer

Question 141

Shift conversion reaction

A. Converts N₂ and H₂ into NH₃
B. Converts CO to CO₂ with steam
C. Is non-catalytic
D. Is highly exothermic

View Answer

Question 142

The rate constant of a chemical reaction increases by increasing the

A. Temperature
B. Pressure
C. Reactant's concentration
D. None of these

View Answer

Question 143

For a first order chemical reaction, the rate constant

A. Changes on changing the concentration units
B. Is not a function of the unit of time
C. Has unit of time⁻¹
D. None ofthese

View Answer

Question 144

For a homogeneous reaction of nth order, the dimension of the rate constant is given by

A. L/(time)n
B. (concentration)1 - n/(time)
C. (concentration)n - 1/(time)
D. None of these

View Answer

Question 145

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenious law is used. What will be this ratio, if transition state theory is used with the same value of E/R?

A. 1.6
B. 2
C. 2.24
D. 2.5

View Answer

Question 146

__________ is the response curve for a step input signal from a reactor.

A. S-curve
B. C-curve
C. I-curve
D. none of these

View Answer

Question 147

Half life period of a chemical reaction is proportional to CA0-1 , if the reaction is of __________ order.

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

View Answer

Question 148

With increase in initial concentration, the fractional conversion of a first order reaction in a given time

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

View Answer

Question 149

During manufacture of H₂SO₄, the oxidation of SO₂ to SO₃ by oxygen is an en- dothermic reaction. The yield of SO₃ will be maximised, if the

A. Temperature is increased
B. Pressure is reduced
C. Temperature is increased and pressure is reduced
D. Temperature is reduced and pressure is increased

View Answer

Question 150

The rate constant of a reaction depends on the

A. Initial concentration of reactants
B. Time of reaction
C. Temperature of the system
D. Extent of reaction

View Answer

Question 151

In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants)

A. A
B. N
C. A+N
D. A-N

View Answer

Question 152

As the chemical reaction proceeds, the rate of reaction

A. Increases
B. Decreases
C. Remains same
D. May increase or decrease depending on the type of reaction

View Answer

Question 153

The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m³ is fed to the reactor at the rate of 0.01 m³ /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k)is (Data: Heat of reaction at 298 K = - 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature))

A. 400
B. 500
C. 600
D. 1000

View Answer

Question 154

A batch reactor is suitable for

A. achieving cent percent conversion of reactants into products.
B. large scale gaseous phase reactions.
C. liquid phase reactions.
D. obtaining uniform polymerisation products in highly exothermic reactions.

View Answer

Question 155

The conversion in a mixed reactor/accomplishing a reaction A 3R is 50% when gaseous reactant 'A' is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is __________ second.

A. 0.5
B. 1
C. 2
D. 3

View Answer

Question 156

Half life period of a chemical reaction is

A. The time required to reduce the concentration of the reacting substance to half its initial value
B. Half of the space time of a reaction
C. Half of the residence time of a reaction
D. None of these

View Answer

Question 157

Chemical reaction rate of a component depends upon the

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

View Answer

Question 158

What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on?

A. Litre/mole.second
B. Moles/litre.second
C. Litre/mole
D. Litre/second

View Answer

Question 159

The fractional volume change between no conversion and complete conversion, for the isothermal gas phase reaction, 2A → R, is

A. 0.5
B. -0.5
C. 1
D. 1.5

View Answer

Question 160

Pick out the correct statement.

A. A lower temperature favours the reaction of lower activation energy
B. The dispersion number for a reactor/vessel is uL/D
C. The rate controlling step in a reaction involving many steps is the fastetst step
D. Pore volume and porosity of a catalyst is measured by Brunaver-Emmet-Teller (BET) technique

View Answer

Question 161

Reverse reaction in a chemical equilibrium is favoured by the

A. Removal of one of the products regularly
B. Increase in the concentration of oneof the products
C. Increase in the concentration of one of the reactants
D. None of these

View Answer

Question 162

An imbalanced chemical reaction equation is against the law of

A. Multiple proportion
B. Conservation of mass
C. Constant proportion
D. None of these

View Answer

Question 163

The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are

A. 2 & 1
B. 11 & 2
C. 2 && 2
D. 1 & 1

View Answer

Question 164

Which of the following is the most suitable for very high pressure gas phase reaction ?

A. Batch reactor
B. Tubular flow reactor
C. Stirred tank reactor
D. Fluidised bed reactor

View Answer

Question 165

Slurry reactors are characterised by the

A. Lack of intraparticle diffusion resistance
B. Presence of two mobile phases
C. Both A and B
D. Neither A nor B

View Answer

Question 166

Pick out the wrong statement.

A. A particular chemical reaction is more temperature sensitive at low temperatures
B. A very high value of equilibrium constant, K (K >> 1) indicates that the reaction is practically irreversible in nature
C. The intercept of the Arrhenious plot is called the 'activation energy'
D. Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions

View Answer

Question 167

Velocity of a chemical reaction

A. Decreases with increase in temperature
B. Increases with increase of pressure of reactants for all reactions
C. Decreases with increase of reactant concentration
D. None of these

View Answer

Question 168

A catalyst loses its activity due to

A. Loss in surface area of the active component
B. Agglomeration of metal particles caused by thermal sintering of the solid surface
C. Covering of the catalytic active sites by a foregin substance
D. All of the above

View Answer

Question 169

Most important characteristics of gas-liquid reactors are the

A. Specific inter-facial area
B. Liquid hold-up
C. Both A and B
D. None of these

View Answer

Question 170

In which of the following gaseous phase reactions, the equilibrium of the reaction remains unaffacted by pressure changes ?

A. 2O? ? 3O?
B. N? + O? ? 2NO
C. 2NO? ? N?O?
D. 2SO? + O? ? 2SO?

View Answer

Question 171

Photo-chemical reactions occur in presence of

A. Sunlight
B. Darkness
C. Solid catalysts
D. Monochromatic radiation only

View Answer

Question 172

A gaseous reactant is introduced in a mixed reactor of 3 litres volume at the rate of 1 litre/second. The space time is __________ seconds.

A. 1
B. 3
C. 1-3
D. 32

View Answer

Question 173

Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure?

A. Langmuir adsorption isotherm
B. Adsorption isobar
C. Freundlich adsorption isotherm
D. None of these

View Answer

Question 174

A balanced chemical reaction equation conforms to the law of

A. Conservation of mass
B. Avagadro's hypothesis
C. Gaseous volumes
D. None ofthese

View Answer

Question 175

Helium-mercury method can be used to determine the __________ of the catalyst particle.

A. Pore volume
B. Solid density
C. Porosity
D. All of the above

View Answer

Question 176

Pick out the wrong statement.

A. The integral method of analysing kinetic data is used when the data is scattered
B. The differential method of analysing kinetic data requires more accurate or larger amounts of data
C. When the reaction rate is independent of temperature, the reaction is said to be of zero order
D. He ratio of volumes of plug flow reactor to that of mixed reactor is always less than one for identical feed composition, flow rate, conversion and for all positive reaction orders

View Answer

Question 177

Which of the following is a controlling factor in very fast heterogeneous reaction?

A. Heat and mass transfer effects
B. Pressure
C. Temperature
D. Composition of reactant

View Answer

Question 178

Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N₂ + 3H₂ ⇋ 2NH₃.

A. Increases
B. Decreases
C. Remains unchanged
D. Unpredictable from the data

View Answer

Question 179

Oil is hydrogenated using nickel catalyst in a __________ reactor.

A. Batch
B. Slurry
C. Fluidised bed
D. Fixed bed

View Answer

Question 180

Ionic reactions occur in

A. Solid state only
B. Liquid state only
C. Solutions
D. Any state

View Answer

Question 181

n' number of plug flow reactors (P.F.R) in series with a total volume 'V' gives the same conversion as one P.F.R. of volume

A. V/n
B. V
C. V.n
D. 1/V

View Answer

Question 182

In an exothermic chemical reaction, the reactants compared to the products have

A. higher temperature
B. more energy
C. less energy
D. same energy.

View Answer

Question 183

Helium-mercury method is used for the measurement of the __________ of the catalyst.

A. Surface area
B. Porosity
C. Pore volume
D. Both B & C

View Answer

Question 184

Which of the following does not produce a change in the value of rate constant of a reaction?

A. Pressure
B. Temperature
C. Concentration and catalyst
D. None of these

View Answer

Question 185

In a CSTR __________ varies with time.

A. Reaction rate
B. Concentration
C. Both A & B
D. Neither A nor B

View Answer

Question 186

For the non catalytic reaction of particles with surrounding fluid, the same needed to achive the same fractional conversion for particles of different unchanging sizes is proportional to the particle diameter, when the __________ is the controlling resistance.

A. Film diffusion
B. Diffusion through ash layer
C. Chemical reaction
D. Either A, B or C

View Answer

Question 187

The extent of a reaction is

A. Different for reactants and products
B. Dimensionless
C. Depends on the stoichiometric co-efficient
D. All of the above

View Answer

Question 188

A catalyst loses its activity due to

A. loss in surface area of the active component.
B. agglomeration of metal particles caused by thermal sintering of the solid surface.
C. covering of the catalytic active sites by a foregin substance.
D. all (a), (b) and (c).

View Answer

Question 189

In the reversible reaction of the type, A + B ⇋ AB, in general

A. Both forward and backward reactions will be exothermic
B. Neither of the reactions will be en-dothermic
C. The combination reaction will be exothermic, while the dissociation reaction will be endothermic
D. The combination reaction will be endothermic, while the dissociation reaction will be exothermic

View Answer

Question 190

A batch reactor suffers from following disadvantage.

A. Poor product quality control
B. High labour and handling cost
C. High shutdown time requirement for emptying, cleaning and refilling
D. All of the above

View Answer

Question 191

The fractional volume change of the system for the isothermal gas phase reaction, A 3B , between no conversion and complete conversion is

A. 0.5
B. 1
C. 2
D. 3

View Answer

Question 192

"A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?A. Inner catalyst core of radius R/8 does not participate in reaction."

A. Inner catalyst core of radius R/8 does not participate in reaction
B. Inner catalyst core of radius R/2 does not participate in reaction
C. Inner catalyst core of radius 7R/8 does not participate in reaction
D. Ffectiveness factor for a zero order reaction can not be 7/8 as it must always be 1

View Answer

Question 193

Transition state theory relates the above quantities as

A. K ∝ e-E/RT
B. K ∝ T.eE/RT
C. K ∝ √T
D. K ∝ T1.5

View Answer

Question 194

The half life period of a first order reaction is

A. Always the same irrespective of the reaction
B. Dependent on initial concentration of the reactants
C. Proportional to the initial concentration of reactants
D. Half the specific rate constant

View Answer

Question 195

The use of space time is preferred over the mean residence time in the design of a/an

A. Batch reactor
B. Ideal tubular-flow reactor
C. Slurry reactor
D. CSTR

View Answer

Question 196

When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value.

A. Twice
B. Half
C. Equal
D. None of these

View Answer

Question 197

The effectiveness factor for large value of Thiele modulus (L√(K/D1)) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm²/second)

A. L√(K/D1)
B. 1/(L√(K/D1))
C. 1
D. ∞

View Answer

Question 198

For a heterogeneous catalytic reaction

A. free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction.
B. a relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important.
C. the catalyst does not form an intermediate complex with the reactant.
D. the surface of the catalyst does not play an important role during reaction.

View Answer

Question 199

Photochemical reaction rate does not depend significantly on temperature, because

A. It is a reversible reaction
B. It is an exothermic reaction
C. The energy of reacting molecules exceeds the activation energy by absorption of light
D. None of these

View Answer

Question 200

Carrier in a catalyst increases its

A. Surface area
B. Activity
C. Performance
D. None of these

View Answer

Question 201

Equilibrium of a chemical reaction as viewed by kinetics is a __________ state.

A. Dynamic steady
B. Static steady
C. Dynamic unsteady
D. None of these

View Answer

Question 202

For the reversible reaction A ⇋ 2B, if the equilibrium constant K is 0.05 mole/litre; starting from initially 2 moles of A and zero moles of B, how many moles will be formed at equilibrium?

A. 0.253
B. 0.338
C. 0.152
D. 0.637

View Answer

Question 203

If CA is the quantity of reactants initially present, the quantity left after 'n' half periods will be equal to

A. (CA)n
B. (1/2)n.CA
C. (CA)1/n
D. (CA)1/2n

View Answer

Question 204

When the reaction is dominated by in-traparticle diffusion, the apparent order of reaction (nD) as measured is related to the true order (n) as

A. ND = (n + 1)/2
B. ND = n/2
C. ND = n + 1
D. None of these

View Answer

Question 205

In case of physical adsorption, the heat of adsorption is of the order of __________ kcal/kg.mole.

A. 100
B. 1000
C. 10000
D. 100000

View Answer

Question 206

When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is

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

View Answer

Question 207

The unit of frequency factor in Arhenious equation is

A. Same as that of rate constant
B. Same as that of activation energy
C. Dimensionless
D. None of these

View Answer

Question 208

A space velocity of 5 hr⁻¹ means that

A. Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour
B. After every 5 hours, reactor is being filled with the feed
C. Cent per cent conversion can be achieved in at least 5 hours
D. A fixed conversion of a given batch of feed takes 5 hours

View Answer

Question 209

Molecularity of a reaction

A. Is always equal to the overall order of reaction
B. May not be equal to the order of reaction
C. Can
D. Both B and C

View Answer

Question 210

For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the __________ is the controlling resistance.

A. Film diffusion
B. Diffusion through ash layer
C. Chemical reaction
D. Either A, B or C

View Answer

Question 211

Holding time for flow reactors is __________ the space time, for constant fluid density

A. Double
B. Triple
C. Equal to
D. None of these

View Answer

Question 212

For a zero order chemical reaction, the

A. Half life period is directly proportion to the initial concentration of the reac-tants
B. Plot of products concentration with time is a straight line through the origin
C. Products concentration increases linerarly with time
D. All of the above

View Answer

Question 213

Pick out the correct statement.

A. A catalyst speeds up the forward reaction but slows shown the reverse reaction
B. Addition of catalyst changes the equilibrium constant
C. Pressure changes do not change the equilibrium concentrations
D. The composition of equilibrium is changed by catalyst

View Answer

Question 214

In the fluid catalytic cracker (FCC), the cracking reaction is __________ (i) and the regeneration is ____________ (ii)

A. (i) exothermic (ii) endothermic
B. (i) exothermic (ii) exothermic
C. (i) endothermic (ii) enodthermic
D. (i) endothermic (ii) exothermic

View Answer

Question 215

A photochemical reaction is

A. Accompanied with emission of light
B. Catalysed by light
C. Initiated by light
D. All of the above

View Answer

Question 216

Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature?

A. Time
B. Useful volume of the tank
C. Diameter of the reactor
D. None of these

View Answer

Question 217

Knudsen diffusion is directly proportional to

A. T
B. √T
C. 1/√T
D. T₂

View Answer

Question 218

Variables affecting the rate of homogeneous reactions are

A. Pressure and temperature only
B. Temperature and composition only
C. Pressure and composition only
D. Pressure, temperature and composition

View Answer

Question 219

The catalytic converter for conversion of SO₂ to SO₃ by contact process should have a feed with SO₂ content between

A. 2-5%
B. 7-10%
C. 12-15%
D. 20-25%

View Answer

Question 220

N' plug flow reactors in series with a total volume 'V' gives the same conversion as a single plug flow reactor of volume 'V' for __________ order reactions.

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

View Answer

Question 221

If pore diffusion is the controlling step in a solid catalysed reaction, the catalyst

A. Porosity is very important
B. Porosity is of less importance
C. Internal surface area is utilised efficiently
D. None of these

View Answer

Question 222

Maximum equilibrium conversion for endothermic reaction is obtained at the __________ temperature.

A. Highest possible
B. Lowest possible
C. Intermediate
D. Room

View Answer

Question 223

A first order reaction requires two equal sized CSTR. The conversion is

A. less when they are connected in series.
B. more when they are connected in series.
C. more when they are connected in parallel.
D. same whether they are connected in series or in parallel.

View Answer

Question 224

BET apparatus

A. measures the catalyst surface area directly.
B. operates at very high pressure.
C. is made entirely of stainless steel.
D. none of these.

View Answer

Question 225

In case of staged packed bed reactors carrying out exothermic reaction, use

A. High recycle for pure gas
B. Plug flow for dilute liquid requiring no large preheating of feed
C. Cold shot operations for a dilute solution requiring large preheating to bring the stream upto the reaction temperature
D. All of the above

View Answer

Question 226

Pick out the wrong statement.

A. Autocatalytic reactions are exemplified by microbial fermentation reactions
B. The slowest step has the greatest influence on the overall reaction rate in case of an irreversible series reaction
C. He fractional conversion at any time is same for both the constant as well as the variable volume system in case of an irreversible unimolecular type first order reaction
D. Ydrolysis of ester in presence of alkali or acid is a zero order reaction

View Answer

Question 227

A multiple reaction may be classified as a __________ reaction.

A. Consecutive or side
B. Parallel or side
C. Mixed
D. All of the above

View Answer

Question 228

Space velocity

A. Describes the extensive operating characteristics of a tubular flow reactor
B. Is the maximum feed rate pre unit volume of reactor for a given conversion
C. Is a measure of the ease of the reaction
D. All of the above

View Answer

Question 229

The rate of reaction of a/an __________ reaction is not affected by temperature rise.

A. Autocatalytic
B. Photochemical
C. Consecutive
D. Zero order

View Answer

Question 230

Pick out the wrong statement.

A. In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time
B. In a semi-batch reactor, one reactant is charged batchwise, while the other reactant is fed continuously
C. In a continuous flow reactor, uniform concentration can not be maintained throughout the vessel even in a well agitated system
D. N a continuous flow reactor, both the reactants and the products flow out continuously

View Answer

Question 231

The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reaction with low activation energy are

A. Always irreversible
B. Insensitive to temperature changes
C. Mostly irreversible
D. Highly temperature sensitive

View Answer

Question 232

In the gaseous phase ammonia formation reaction (N₂ + 3H₂ ⇋ 2NH₃), the value of the equilibrium constant depends on the

A. Total pressure of the system
B. Volume of the reactor
C. Temperature
D. Initial concentration of N₂ and H₂

View Answer

Question 233

Pick out the wrong statement pertaining to space velocity of flow reactors.

A. The unit of space velocity is (time)-1 .
B. The space velocity of 3 hr-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour.
C. The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.
D. none of these.

View Answer

Question 234

Pick out the wrong statement.

A. Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition
B. Alumina is added as a promoter to iron catalyst in ammonia synthesis reaction
C. Activation energy for a reaction is obtained from the intercept of the Ar-rhenious plot
D. Presence of inerts affects the equilibrium conversion of reactants in a chemical reaction

View Answer

Question 235

Pick out the wrong statement.

A. In a multistep reaction, the slowest step is the rate determining step
B. In general, the rate of a reaction becomes triple for every 10°C rise in temperature
C. Slow chemical reactions have generally high values of activation energy
D. Molecularity of a reaction can not be zero but the order of a reaction can be zero

View Answer

Question 236

The single parameter model proposed for describing non-ideal flow is the __________ model.

A. Tank in series
B. Dispersion
C. Both A & B
D. Neither A nor B

View Answer

Question 237

A plug-flow reactor is characterised by

A. High capacity
B. Presence of axial mixing
C. Presence of lateral mixing
D. Constant composition and temperature of reaction mixture

View Answer

Question 238

Pick out the wrong statement.

A. Or a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity
B. Or an ideal mixed reactor at steady state, the exit stream has the same composition as fluid within the reactor and the space time is equivalent to holding time for constant density system
C. Lug flow reactor (PFR) is always smaller than mixed reactor for all positive reaction orders for a particular duty
D. Eaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction

View Answer

Question 239

Pick out the wrong statement.

A. Exit age description function (E) and internal age distribution function (I) are related as,E = - dI/d0 .#
B. Chmisorption studies are useful in the determination of catalyst surface area and pore size distribution
C. A higher temperature favours the reaction of higher activation energy
D. A catalyst increases the potential energy barrier over which the reactants must pass to form products

View Answer

Question 240

In an ideal P.F.R. at steady state conditions

A. The composition of reactants remains constant along a flow path
B. The conversion of the reactant varies from point to point along a flow path
C. There is no lateral mixing of fluid
D. There may be diffusion along the flow path

View Answer

Question 241

Unreacted core model' represents the reaction involving

A. Combustion of coal particles
B. Roasting of sulphide ores
C. Manufacture of carbon disulphide from elements
D. None of these

View Answer

Question 242

The sequence in which three CSTR's of volumes 5, 10 and 15 m³ will be connected in series to obtain the maximum production in a second order irreversible reaction is

A. 15, 10, 5
B. 5, 10, 15
C. 10, 5, 15
D. 10, 15, 2005

View Answer

Question 243

Pick out the wrong statement.

A. Visible radiation provides the necessary activation energy in photochemical reactions
B. The order and molecularity of a complex reaction may not be the same
C. For a second order reaction, the slope of the graph/plot between rate and (concentration) is equal to the rate constant (k)
D. Molecularity of the reaction is always a whole number greater than zero

View Answer

Question 244

If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is

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

View Answer

Question 245

A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length

A. Decreases
B. Increases
C. Is at the highest allowable temperature throughout
D. First increases and then decreases

View Answer

Question 246

The rate of forward reaction, at chemical equilibrium is____the rate of backward reaction.

A. More than
B. Less than
C. Equal to
D. Either B or C

View Answer

Question 247

__________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction.

A. Gas film diffusion
B. Ash diffusion
C. Chemical reaction
D. None of these

View Answer

Question 248

For a heterogenous catalytic reaction, A + B → C, with equimole feed of A and B, the initial rate - rA0 is invariant with total pressure. The rate controlling step is

A. Surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase
B. Surface reaction between absorbed A and absorbed B
C. Surface reaction between A in the gas phase and absorbed B
D. Desorption of C

View Answer

Question 249

The rate of a chemical reaction is almost doubled for every 10°C rise in temperature. The rate will increase __________ times, if the temperature rises form 10 to 100°C.

A. 256
B. 512
C. 112
D. 612

View Answer

Question 250

The rate constant of a chemical reaction decreases by decreasing the

A. pressure
B. concentration of reactants
C. temperature
D. duration of reaction

View Answer

Question 251

In the hydrodealkylation of toluene to benzene, the following reactions occur:C₇H₈ + H₂ → C₆H₆ + CH₄2C₆H₆ ⇋ C₁₂H₁₀ + H₂Toluene and hydrogen are fed to a reactor in a molar ratio 1:5.80% of the toluene gets converted and the selectivity of benzene(defined as moles of benzene formed/moles of toluene converted) is 90%. The fractional conversion of hydrogen is

A. 0.16
B. 0.144
C. 0.152
D. 0.136

View Answer

Question 252

Which of the following will give maximum gas conversion ?

A. Fixed bed reactor.
B. Fluidised bed reactor.
C. Semi-fluidised bed reactor.
D. Plug-flow catalytic reactor.

View Answer

Question 253

The reason why a catalyst increases the rate of reaction is that, it

A. Decreases the energy barrier for reaction
B. Increases the activation energy
C. Decreases the molecular collision diameter
D. None of these

View Answer

Question 254

In a continuous flow stirred tank reactor, the composition of the exit stream

A. Is same as that in the reactor
B. Is different than that in the reactor
C. Depends upon the flow rate of inlet stream
D. None of these

View Answer

Question 255

A batch adiabatic reactor at an initial temperature of 373°K is being used for the reaction, A → B. Assume the heat of reaction is - 1kJ/mole at 373°K and heat capacity of both A and B to be constant and equal to 50J/mole.K. The temperature rise after a conversion of 0.5 will be

A. 5°C
B. 10°C
C. 20°C
D. 100°C

View Answer

Question 256

Which of the following is a characteristic of an ideal plug flow reactor?

A. Axial dispersion
B. Flat velocity profile
C. Uniform mixing
D. None of these

View Answer

Question 257

A backmix reactor

A. Is same as plug-flow reactor
B. Is same as ideal stirred tank reactor
C. Employs mixing in axial direction only
D. Is most suitable for gas phase reaction

View Answer

Question 258

BET apparatus

A. Measures the catalyst surface area directly
B. Operates at very high pressure
C. Is made entirely of stainless steel
D. None of these

View Answer

Question 259

The percent conversion of ethanol in the reactor is

A. 100
B. 97.5
C. 95
D. 2.5

View Answer

Question 260

An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time.

A. Increase
B. Increase exponentially
C. Decrease
D. Remain unchanged

View Answer

Question 261

The dimensions of rate constant for reaction 3A → B are (l/gm mole)/min. Therefore the reaction order is

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

View Answer

Question 262

To maximise the formation of R in the simultaneous reactionA + B → R , rR = 2CA0.5.CB2 A + B → S , rS = 1.5 CA . CB We should have

A. Low CA, low CB
B. Low CA, high CB
C. High CA, low CB
D. High CA, high CB

View Answer

Question 263

The residence time distribution of an ideal CSTR is

A. 1/τ exp (-t/τ)
B. Τ exp (-t/τ)
C. Exp(-t/τ)
D. 1/τ (-t/τ)

View Answer

Question 264

For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a

A. Batch reactor is preferred over a single CSTR for high yield
B. Tubular reactor is preferred over a single CSTR for high yield
C. Both A and B
D. Single CSTR is the most suitable

View Answer

Question 265

Signal normally used to study non-ideal flow by stimulus response technique is __________ input.

A. Pulse
B. Step
C. Both A & B
D. Neither A nor B

View Answer

Question 266

From collison theory, the reaction rate constant is proportional to

A. Exp(- E/RT)
B. Exp(- E/2RT)
C. √T
D. Tm.exp(- E/RT)

View Answer

Question 267

The enzyme which can catalyse the conversion of glucose to ethyl alcohol is

A. Invertase
B. Maltase
C. Diastase
D. Zymase

View Answer

Question 268

Pick out the wrong statement.

A. In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration of A
B. Transition state theory approaches the problem of calculating reaction rates by concentrating on the idea of activated complexes
C. According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases
D. If the rate of an irreversible reaction, A + B → 2C is k.CA.CB, then the reaction is always elementary

View Answer

Question 269

Which of the following resistances is not involved in a gas phase catalytic (gas- solid) reaction?

A. Ash resistance
B. Gas film and pore surface diffusion resistances for reactants
C. Surface phenomenon resistance
D. Gas film and pore surface diffusion resistances for products

View Answer

Question 270

reactant and product streams). The amount of heat to be removed is

A. 2/3 kW
B. 1kW
C. 5/3 kW
D. 4kW

View Answer

Question 271

BET apparatus is used to determine the

A. Specific surface of a porous catalyst
B. Pore size distribution
C. Pore diameter
D. Porosity of the catalyst bed

View Answer

Question 272

Which of the following will favour the reverse reaction in a chemical equilibrium reaction?

A. Increasing the concentration of one of the reactants
B. Increasing the concentration of one or more of the products
C. Removal of at least one of the products at regular interval
D. None of these

View Answer

Question 273

Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about __________ minutes.

A. 3
B. 4
C. 6
D. 8

View Answer

Question 274

A pulse tracer is introduced in an ideal CSTR (with a mean residence time ι) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be

A. 2τ
B. 0.5τ
C. τ/0.693
D. 0.693τ

View Answer

Question 275

An exothermic reaction takes place in an adiabatic reactor. The product temperature __________ reactor feed temperature.

A. Is always equal to
B. Is always greater than
C. Is always less than
D. May be greater or less than

View Answer

Question 276

If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is

A. Not feasible
B. Just feasible
C. Very much feasible
D. Unpredictable as ΔG is no measure of feasibility of a reaction

View Answer

Question 277

The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the

A. Increased temperature reduces the activation energy
B. Fraction of molecules having threshold energy increases
C. Collision frequency increases
D. Value of threshold energy decreases

View Answer

Question 278

In autocatalytic reactions,

A. One of the reactants acts as a catalyst
B. One of the products acts as a catalyst
C. Catalysts have very high selectivity
D. No catalyst is used

View Answer

Question 279

Exposure of a photographic plate to produce a latent image is an example of __________ reaction.

A. Very slow
B. Very fast
C. Photochemical
D. Both B and C

View Answer

Question 280

Pick out the correct statement

A. Reactions with high activation energies are very temperature sensitive
B. Chemical equilibrium is a static state
C. A photochemical reaction is catalysed by light
D. A chemical reaction occurs when the energy of the reacting molecule is less than the activation energy of the reaction

View Answer

Question 281

The vessel dispersion number (D/μL) for plug flow is

A. 0
B. 500
C. 750
D. ∞

View Answer

Question 282

Arrhenious equation represents graphically the variation between the __________ and temperature.

A. Rate of reaction
B. Frequency factor
C. Rate constant
D. Activation energy

View Answer

Question 283

__________ gas is normally employed in B.E.T.method of finding out the surface area of catalyst.

A. N₂
B. H₂
C. CO₂
D. He

View Answer

Question 284

In case of the irreversible unimolecular type, first order reaction, the fractional conversion at any time for constant volume system as compared to variable volume system is

A. More
B. Less
C. Same
D. Either A or B, depends on other factors

View Answer

Question 285

Pick out the correct statement

A. Reactions with high activation energies are very temperature sensitive.
B. Chemical equilibrium is a static state.
C. A photochemical reaction is catalysed by light.
D. A chemical reaction occurs when the energy of the reacting molecule is less than the activation energy of the reaction.

View Answer

Question 286

A catalyst promoter

A. Improves the activity of a catalyst
B. Acts as a catalyst support
C. Itself has very high activity
D. All of the above

View Answer

Question 287

Pure A in gas phase enters a reactor 50% of this A is converted to B through the reaction, A 3B. Mole fraction of A in the exit stream is

A. 1-2
B. 1-3
C. 1-4
D. 1-5

View Answer

Question 288

Effectiveness factor of a catalyst pellet is a measure of the __________ resistance.

A. Pore diffusion
B. Gas film
C. Chemical reaction
D. None of these

View Answer

Question 289

With decrease in temperature, the equilibrium conversion of a reversible endother- mic reaction

A. Decreases
B. Increases
C. Remains unaffected
D. Increases linearly with temperature

View Answer

Question 290

A first order irreversible reaction, A → B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors.

A. Both conversion as well as concentration are same
B. Conversion in both will be the same but concentrations will be different
C. Both the conversion as well as concentrations will be different
D. None of these

View Answer

Question 291

Rate of an autocatalytic chemical reaction is a function of

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

View Answer

Question 292

Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an __________ reaction.

A. Elementary
B. Parallel
C. Consecutive
D. None of these

View Answer

Question 293

The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called

A. A ferment or an enzyme
B. Haemoglobin
C. Fungi
D. None of these

View Answer

Question 294

Calcination reaction of limestone (CaCO₃ → CaO + CO₂) goes to completion in the rotary kiln, because

A. CaO is not dissociated
B. CO₂ escapes continuously
C. Of high calcination temperature
D. CaO is more stable than CaCO₃

View Answer

Question 295

With increase in temperature, the equilibrium conversion of a reversible exothermic reaction

A. Decreases
B. Increases
C. Remains unaffected
D. Decreases linearily with temperature

View Answer

Question 296

In a reversible reaction, a catalyst increases the rate of forward reaction

A. Only
B. To a greater extent than that of the backward reaction
C. And decreases that of the backward reaction
D. And the backward reaction equally

View Answer

Question 297

Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in

A. Blood
B. Saliva
C. Intestine
D. Gland

View Answer

Question 298

The performance equations for constant density systems are identical for

A. P.F.R. and backmix reactor
B. P.F.R. and batch reactor
C. P.F.R, batch reactor and backmix reactor
D. Batch reactor and backmix reactor

View Answer

Question 299

For multiple reactions, the flow pattern within the vessel affects the

A. Size requirement
B. Distribution of reaction products
C. Both A and B
D. Neither A nor B

View Answer

Question 300

Semibatch reactor is preferred, when a/an

A. A highly exothermic reaction is to be controlled
B. Undersirable side reaction (at high concentration of one of the reactants) is to be avoided
C. A gas is to be reacted with liquid (e.g. hydrogenation of fat)
D. All of the above

View Answer

Question 301

Thermodynamic equilibrium constant in a system is affected by

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

View Answer

Question 302

The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the __________ energy.

A. activation
B. potential
C. binding
D. threshold

View Answer

Question 303

Transition state theory gives the rate constant as

A. K α e-E/RT
B. K α eE/RT
C. K α T . e-E/RT
D. K α √T . e-E/RT

View Answer

Question 304

The decomposition of A into B is represented by the exothermic reaction, A ⇋ 2B. To achieve maximum decomposition, it is desirable to carry out the reaction.

A. At high P and high T
B. At low P and high T
C. At low P and low T
D. At high P and low T

View Answer

Question 305

A second order reaction of the form A + B → C is called a pseudo-first order reaction, when

A. CA0 = CB0
B. CA0 > CB0
C. CB0 > CA0
D. CB0 ≥ CB0

View Answer

Question 306

Rate of a chemical reaction is not influenced by the

A. Catalyst
B. Temperature
C. Reactants concentration
D. Number of molecules of reactants taking part in a reaction

View Answer

Question 307

The gas phase reaction 2A ⇋ B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is

A. 2-3
B. 5-8
C. 1-3
D. 3-8

View Answer

Question 308

The value of 'n' for a chemical reaction A → B, whose reaction rate is → CAn, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled.

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

View Answer

Question 309

A catalyst is said to be a negative catalyst, ifit

A. Retards the rate of reaction
B. Reduces the value of equilibrium constant
C. Does not initiate the reaction
D. All of the above

View Answer

Question 310

Half-life period for a first order reaction is __________ the initial concentration of the reactant.

A. Directly proportional to
B. Inversely proportional to
C. Independent of
D. None of these

View Answer

Question 311

A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are

A. Equal in size
B. Of different sizes
C. Of such size that the ratio of their volumes is < 5
D. None of these

View Answer

Question 312

Which of the following is the optimum operating condition for an exothermic reversible reaction taking place in a plug-flow reactor?

A. Temperature should be high in the beginning and decreased towards the end of the reaction
B. Very low temperature should be used throughout the reaction
C. Very high temperature should be used throughout the reaction
D. None of these

View Answer

Question 313

If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the

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

View Answer

Question 314

Consider the 'n' th order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction (t1/2) and the initial reactant concentration (CA0) gives a straight line plot?

A. CA0 Vs t1/2
B. Ln CA0 Vs t1/2
C. CA0 Vs ln t1/2
D. Ln CA0 Vs ln t1/2

View Answer

Question 315

The role of a catalyst in a chemical reaction is to change the

A. Equilibrium constant
B. Activation energy
C. Final products
D. Heat of reaction

View Answer

Question 316

Collision theory gives the rate constant for bimolecular reaction as

A. K α √T.e-E/RT
B. K α eE/RT
C. K α e-E/RT
D. None of these

View Answer

Question 317

Pick out the wrong statement.

A. A catalyst does not alter the final position of equilibrium in a reversible reaction
B. A catalyst initiates a reaction
C. A catalyst is specific in reaction
D. A catalyst remains unchanged in chemical composition at the end the reaction

View Answer

Question 318

A reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction.

A. Catalytic
B. Autocatalytic
C. Photochemical
D. None of these

View Answer

Question 319

A batch reactor is characterised by

A. Constant residence time
B. Variation in extent of reaction and properties of the reaction mixture with time
C. Variation in reactor volume
D. Very low conversion

View Answer

Question 320

The single parameter model proposed for describing non-ideal flow is the __________ model.

A. tank in series
B. dispersion
C. both (a) & (b)
D. neither (a) nor (b).

View Answer

Question 321

Cold shot cooling is only practical when the feed temperature is __________ than the reaction temperature.

A. Higher
B. Much higher
C. Lower
D. Much lower

View Answer

Question 322

Reaction rate of a first order reaction, which is half completed in 23 minutes will be

A. 0.03 sec⁻¹
B. 0.03 min⁻¹
C. 0.03 hr⁻¹
D. 0.05 min⁻¹

View Answer

Question 323

For the gaseous reaction 2A → B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is

A. 1
B. -0.5
C. -0.25
D. 0

View Answer

Question 324

Pick out the wrong statement:

A. Chemical reactions with high activation energy are very temperature sensitive
B. A flat velocity profile exists in a plug flow reactor
C. The residence time for all the elements of fluid in case of a P.F.R. need not be same
D. Half life of a reaction increases with increased initial concentration for reaction orders more than one

View Answer

Question 325

For series reaction, the relative yield

A. Is always greater for plug-flow reactor than for the single CSTR of the same volume
B. Statement in A is wrong
C. Decreases with increasing conversion
D. Both A and C hold good

View Answer

Question 326

If the time required to change the concentration of reactant to half its original value is independent of the initial concentration, the order of reaction is

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

View Answer

Question 327

On application of pressure to the equilibrium system, ice ⇋ water; which of the following phenomenon will occur?

A. Water will evaporate
B. Equilibrium will not be attained
C. More ice will be formed
D. More water will be formed

View Answer

Question 328

A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A → R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: CA0= 5 kmole/m³ ; XA = 0.5; Feed temperature = reactor temperature = 40°C. Rate constant at 40°C = 1 min⁻¹ ; (ΔH) = - 40kJ/mole; ρ = 1000kg/m³ CP = 4 J/gm.°C ; q = 10⁻³ m³/min (ρ and CP are same for the reactant and product streams). The amount of heat to be removed is

A. 2/3 kW
B. 1kW
C. 5/3 kW
D. 4kW

View Answer

Question 329

The reaction between oxygen and organic material is a/an __________ reaction.

A. exothermic
B. endothermic
C. biochemical
D. photochemical

View Answer

Question 330

If in the gaseous phase reaction, N₂O₄ ⇋ 2NO₂, x is the part of N₂O₄ which dissociates, then the number of molecules at equilibrium will be

A. (1 + x)
B. (1 - x)
C. (1 + x)²
D. (1 - x)²

View Answer

Question 331

Autocatalytic reactions are best carried out in a

A. CSTR
B. CSTR in series
C. Plug flow reactor
D. Recycle reactor

View Answer

Question 332

A high space velocity means that a given

A. Reaction can be accomplished with small reactor
B. Conversion can be obtained with a high feed rate
C. Both A and B
D. None of these

View Answer

Question 333

Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature?

A. Pore diffusion
B. Film diffusion
C. Ash layer diffusion
D. Chemical reaction

View Answer

Question 334

In an ideal mixed reactor (at steady state), the

A. Space time is equivalent to holding time for constant density systems
B. Composition throughout the reactor remains same
C. Exit stream has the same composition as the fluid within the reactor
D. All of the above

View Answer

Question 335

When all the limiting reactant is consumed in the reaction, the operational yield __________ the relative yield.

A. Is greater than
B. Is smaller than
C. Equals
D. Can be either greater or smaller than (depends on the type of reaction)

View Answer

Question 336

Pick out the wrong statement.

A. The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively
B. Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant
C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty
D. N an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in logitudinal direction

View Answer

Question 337

A chemical reaction, A → 3B, is conducted in a constant pressure vessel. Starting with pure A, the volume of the reaction mixture increases 3 times in 6 minutes. The fractional conversion is

A. 0.33
B. 0.5
C. 1
D. Data insufficient, can't be predicted

View Answer

Question 338

The reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction.

A. Biochemical
B. Photochemical
C. Catalytic
D. Autocatalytic

View Answer

Question 339

The space time is equivalent to the holding time in a steady state mixed reactor for

A. Non-isothermal gas reaction
B. Variable fluid density systems
C. Constant fluid density systems
D. Gas reactions with changing no. of moles

View Answer

Question 340

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to

A. The intrinsic activation energy E
B. (E + ED) where ED is activation due to diffusion
C. (E + ED)/2
D. ED/2

View Answer

Question 341

Non-catalytic fluid-solid reactions are represented by __________ model.

A. Continuous reaction
B. Unreacted core
C. Both A and B
D. Neither A and B

View Answer

Question 342

Exothermic reactions are best carried out in

A. A CSTR
B. CSTR in series
C. A plug flow reactor followed by CSTR
D. CSTR followed by a plug flow reactor

View Answer

Question 343

Reactions with high activation energy are

A. Very temperature sensitive
B. Temperature insensitive
C. Always irreversible
D. Always reversible

View Answer

Question 344

Effectiveness factor (E) of a catalyst pellet is defined as, E = (actual rate within pore of catalyst/rate if notsnowed by pore diffusion) Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus)

A. Tan hT/T
B. Tan T/T
C. Tan hT/tan T
D. None of these

View Answer

Question 345

In case of __________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds.

A. Catalytic
B. Parallel
C. Series
D. Auto catalytic

View Answer

Question 346

6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO2 and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant ?

A. 100%
B. 95%
C. 75%
D. 20%

View Answer

Question 347

A back mix reactor is

A. Suitable for gas phase reactions
B. Ideal at very low conversion
C. Same as plug flow reactor (PFR)
D. Same as ideal stirred tank reactor

View Answer

Question 348

When an exothermic reversible reaction is conducted adiabatically, the rate of reaction

A. Continuously increases
B. Continuously decreases
C. Passes through a maximum
D. Passes through a minimum

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Question 349

The exit age distribution of fluid leaving a vessel is used to know the

A. Activation energies of a reaction
B. Reaction mechanism
C. Extent of non-ideal flow in the vessel
D. None of these

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Question 350

In a semi-batch reactor

A. Velocity of reaction can be controlled
B. Maximum conversion can be controlled
C. Both the reactants flow counter-currently
D. Residence time is constant

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Question 351

Catalyst carriers

A. Have very high selectivity
B. Increase the activity of a catalyst
C. Provide large surface area with a small amount of active material
D. Inhibit catalyst poisoning

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Question 352

For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min⁻¹ . What will be the conversion for a PFR with a space velocity of 0.2 min⁻¹? Assume that all the other operating conditions are the same for CSTR and PFR.

A. 0.15
B. 0.3
C. 0.6
D. 0.9

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Question 353

'If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the

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

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Question 354

Promoter.

A. Initiates a chemical reaction and is a catalyst by itself
B. Atlers the position of equilibrium in a reversible reaction
C. Increases the number of active centres by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals
D. All of the above

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Question 355

If helium is introduced in a reactor containing O₂, SO₂ and SO₃ at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO₃ (as per Le Chatlier principle)

A. Decreases
B. Increases
C. Remains unaltered
D. Changes unpredictably

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Question 356

The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is __________ that of mixed reactor.

A. Greater than
B. Equal to
C. Smaller than
D. Unpredictable from the data

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Question 357

Which of the following is the most suitable for very high pressure gas phase reaction?

A. Batch reactor
B. Tubular flow reactor
C. Stirred tank reactor
D. Fluidised bed reactor

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Question 358

For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the __________ adsorption.

A. physical
B. chemical
C. both (a) and (b)
D. neither (a) nor (b)

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Question 359

A Catalyst

A. Increases the equilibrium concentration of the product
B. Changes the equilibrium constant of the reaction
C. Shortens the time to reach the equilibrium
D. None of these

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Question 360

In case of a P.F.R., there

A. May be lateral mixing of fluid
B. Should not be any mixing along the flow path
C. Both A and B
D. Neither A nor B

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Question 361

The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an __________ reaction.

A. Elementary
B. Non-elementary
C. Parallel
D. Autokinetic

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Question 362

Which of the following factors control the design of a fluid-solid reactor?

A. Reaction kinetics for single particle,
B. Size distribution of solids beingtreated
C. Flow patterns of solids and fluid in the reactor
D. All of the above

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Question 363

For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is

A. 2
B. 4
C. 11
D. 22

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Question 364

For an autocatalytic reactor, the suitable reactor set up is

A. P.F. reactors in series
B. CSTR in series
C. CSTR followed by P.F. reactor
D. P.F. reactor followed by CSTR

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Question 365

Half life period of a first order irreversible reaction A → B is

A. K/2
B. Ln k/2
C. Ln 2/k
D. Ln 0.5/k

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Question 366

With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion)

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

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Question 367

The equilibrium constant K of a chemical reaction depends on

A. Temperature only
B. Pressure only
C. Temperature and pressure
D. Ratio of reactants

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Question 368

For every 10°C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70°C, the rate of reaction increases __________ times.

A. 8
B. 12
C. 16
D. 32

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Question 369

In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO₂ to SO₃ is accomplished by a __________ reaction.

A. Non-catalytic homogeneous
B. Non-catalytic heterogeneous
C. Catalytic homogenous
D. Catalytic heterogeneous

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Question 370

Sulphuric acid is used as a catalyst in the

A. Hydrogenation of oils
B. Gas phase oxidation of SO₂ in chamber process
C. Alkylation of hydrocarbons
D. None of these

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Question 371

Pick out the correct statement.

A. In catalytic reactions, the catalyst reacts with the reactants.
B. A catalyst initiates a chemical reaction.
C. A catalyst lowers the activation energy of the reacting molecules.
D. A catalyst can not be recovered chemi cally unchanged at the end of the chemical reaction.

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