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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

__________ explains the mechanism of catalysis.

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

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Question 2

'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

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Question 3

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 4

The rate constant of a chemical reaction decreases by decreasing the

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

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Question 5

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 6

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

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Question 7

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

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

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Question 8

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

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Question 9

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).

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Question 10

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

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

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Question 11

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 12

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 13

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.

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Question 14

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 15

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

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Question 16

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.

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Question 17

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 18

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.

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Question 19

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 20

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

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Question 21

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).

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Question 22

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

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Question 23

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 24

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.

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Question 25

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

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Question 26

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 27

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.

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Question 28

Radioactive decay follows __________ order kinetics.

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

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Question 29

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 30

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.

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Question 31

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.

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Question 32

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.

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Question 33

'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 34

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

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Question 35

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.

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Question 36

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 37

__________ 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

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Question 38

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 39

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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