Chemical Reaction Engineering MCQs

Question 1

There is no correspondence between stoichiometry and the rate equation in case of a/an __________ reaction.

Accepted Answer

Non-elementary

Answer

Elementary

Answer

Multiple

Answer

Autocatalytic

Question 2

For a zero order reaction, the concentration of product increases with the

Accepted Answer

Increase of reaction time

Answer

Increase in initial concentration

Answer

Total pressure

Answer

Decrease in total pressure

Question 3

The conversion for a first order liquid phase reaction. A → B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be

Accepted Answer

75

Answer

60

Answer

90

Answer

100

Question 4

The rate constant of a first order reaction depends on the

Accepted Answer

Temperature

Answer

Concentration of the reactant

Answer

Concentration of the product

Answer

Time

Question 5

For all positive reaction orders for a particular duty,

Accepted Answer

Mixed reactor is always larger than the plug-flow reactor

Answer

Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

Answer

Reactor size is independent of the type of flow

Answer

Density variation during reaction affects design

Question 6

If n = overall order of a chemical reaction. a = initial concentration of reactant. t = time required to complete a definite fraction of the reaction. Then pick out the correct relationship.

Accepted Answer

$${	ext{t}} \propto \frac{1}{{{{	ext{a}}^{{	ext{n}} - 1}}}}$$

Answer

$${	ext{t}} \propto \frac{1}{{{{	ext{a}}^{	ext{n}}}}}$$

Answer

$${	ext{t}} \propto \frac{1}{{{{	ext{a}}^{{	ext{n}} + 1}}}}$$

Answer

$${	ext{t}} \propto {{	ext{a}}^{	ext{n}}}$$

Question 7

In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for

Accepted Answer

Slow reactions in catalyst of small pore diameter

Answer

Fast reactions in catalyst of small pore diameter

Answer

Fast reaction in catalyst of large pore diameter

Answer

Slow reactions in catalyst of large pore diameter

Question 8

For a mixed flow reactor operating at steady state, the rate of reaction is given by

Accepted Answer

$$\frac{{{{	ext{F}}_{{{	ext{A}}_{	ext{0}}}}}}}{{	ext{V}}} \cdot {{	ext{X}}_{	ext{A}}}$$

Answer

$$\frac{{{{	ext{F}}_{{{	ext{A}}_{	ext{0}}}}}}}{{	ext{V}}} - \frac{{{	ext{d}}{{	ext{C}}_{	ext{A}}}}}{{{	ext{dt}}}}$$

Answer

$$\frac{{{{	ext{F}}_{{{	ext{A}}_{	ext{0}}}}}}}{{	ext{V}}} + \frac{{{	ext{d}}{{	ext{C}}_{	ext{A}}}}}{{{	ext{dt}}}}$$

Answer

$$ - \frac{{{	ext{d}}{{	ext{C}}_{	ext{A}}}}}{{{	ext{dt}}}}$$

Question 9

The catalyst in a second order reversible reaction increases the rate of the forward reaction

Accepted Answer

And backward reaction equally

Answer

And decreases that of backward reaction

Answer

Only

Answer

To a greater extent than that of the backward reaction