Chemical Reaction Engineering MCQs

Question 1

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

Accepted Answer

Insensitive to temperature changes

Answer

Always irreversible

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Mostly irreversible

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Highly temperature sensitive

Question 2

In a semi-batch reactor,

Accepted Answer

Velocity of reaction can be controlled

Answer

Mixing takes place in axial direction only

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Condition similar to plug flow reactor exists

Answer

Residence time is constant

Question 3

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

Accepted Answer

Activation energy

Answer

Equilibrium constant

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Heat of reaction

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None of these

Question 4

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

Accepted Answer

Temperature

Answer

Pressure

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Both A & B

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Neither A nor B

Question 5

The energy of activation of a chemical reaction

Accepted Answer

Is the minimum energy which the molecules must have before the reaction can take place

Answer

Is same as heat of reaction at constant pressure

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Varies as fifth power of the temperature

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Both B and C

Question 6

Backmixing is most predominant in

Accepted Answer

A single CSTR

Answer

A well stirred batch reactor

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A plug-flow reactor

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CSTR's connected in series

Question 7

Pick out the wrong statement.

Accepted Answer

In a continuous flow reactor, uniform concentration can not be maintained throughout the vessel even in a well agitated system

Answer

In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time

Answer

In a semi-batch reactor, one reactant is charged batchwise, while the other reactant is fed continuously

Answer

In a continuous flow reactor, both the reactants and the products flow out continuously

Question 8

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.

Accepted Answer

4

Answer

3

Answer

6

Answer

8

Question 9

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

Accepted Answer

Exothermic

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Endothermic

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Biochemical

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Photochemical