Chemical Reaction Engineering MCQs

Question 1

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.

Accepted Answer

Conversion in both will be the same but concentrations will be different

Answer

Both conversion as well as concentration are same

Answer

Both the conversion as well as concentrations will be different

Answer

None of these

Question 2

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

Accepted Answer

Equals

Answer

Is greater than

Answer

Is smaller than

Answer

Can be either greater or smaller than (depends on the type of reaction)

Question 3

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

Accepted Answer

Reaction is elementary with a molecularity of 2

Answer

Molecularity of the reaction is 2, but the reaction may not be elementary

Answer

Reaction may be elementary with molecularity of 2

Answer

Reaction is elementary but the molecularity may not be 2

Question 4

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

Accepted Answer

A+N

Answer

A

Answer

N

Answer

A-N

Question 5

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?

Accepted Answer

Litre/mole.second

Answer

Moles/litre.second

Answer

Litre/mole

Answer

Litre/second

Question 6

A back mix reactor is

Accepted Answer

Same as ideal stirred tank reactor

Answer

Suitable for gas phase reactions

Answer

Ideal at very low conversion

Answer

Same as plug flow reactor (PFR)

Question 7

A batch reactor is

Accepted Answer

Suitable for liquid phase reactions involving small production rate

Answer

Suitable for gas-phase reactions on commercial scale

Answer

Least expensive to operate for a given rate

Answer

Most suitable for very large production rate

Question 8

A Catalyst

Accepted Answer

Shortens the time to reach the equilibrium

Answer

Increases the equilibrium concentration of the product

Answer

Changes the equilibrium constant of the reaction

Answer

None of these

Question 9

A catalyst promoter

Accepted Answer

Improves the activity of a catalyst

Answer

Acts as a catalyst support

Answer

Itself has very high activity

Answer

All of the above