Chemical Reaction Engineering MCQs

Question 1

A catalyst loses its activity due to

Accepted Answer

All of the above

Answer

Loss in surface area of the active component

Answer

Agglomeration of metal particles caused by thermal sintering of the solid surface

Answer

Covering of the catalytic active sites by a foregin substance

Question 2

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

Accepted Answer

Ash resistance

Answer

Gas film and pore surface diffusion resistances for reactants

Answer

Surface phenomenon resistance

Answer

Gas film and pore surface diffusion resistances for products

Question 3

What is the dispersion number for a plug flow reactor?

Accepted Answer

0

Answer

$$\infty $$

Answer

1

Answer

-1

Question 4

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

Accepted Answer

Ash

Answer

Gas film

Answer

Chemical reaction

Answer

None of these

Question 5

Pick out the wrong statement.

Accepted Answer

Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty

Answer

The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively

Answer

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

Answer

In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in logitudinal direction

Question 6

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

Accepted Answer

Activation

Answer

Potential

Answer

Binding

Answer

Threshold

Question 7

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

Accepted Answer

Moving bed reactor

Answer

Fluidised bed reactor

Answer

Fixed bed reactor

Answer

None of these

Question 8

The reactions of high molecularity are rare, because

Accepted Answer

Of low probability of many body collisions

Answer

Of very large activation energy of many bodies

Answer

Many body collisions are not favoured energetically

Answer

Of requirement of very large concentration for such reactions

Question 9

Molecularity of a reaction

Accepted Answer

Both B and C

Answer

Is always equal to the overall order of reaction

Answer

May not be equal to the order of reaction

Answer

Can't have a fractional value