Chemical Reaction Engineering MCQs

Question 1

A space velocity of 5 hr-1 means that

Accepted Answer

Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour

Answer

After every 5 hours, reactor is being filled with the feed

Answer

Cent per cent conversion can be achieved in at least 5 hours

Answer

A fixed conversion of a given batch of feed takes 5 hours

Question 2

An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time.

Accepted Answer

Decrease

Answer

Increase

Answer

Increase exponentially

Answer

Remain unchanged

Question 3

For multiple reactions, the flow pattern within the vessel affects the

Accepted Answer

Both A and B

Answer

Size requirement

Answer

Distribution of reaction products

Answer

Neither A nor B

Question 4

If helium is introduced in a reactor containing O2, SO2 and SO3 at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO3 (as per Le Chatlier principle)

Accepted Answer

Decreases

Answer

Increases

Answer

Remains unaltered

Answer

Changes unpredictably

Question 5

The temperature dependence of reaction rate constant (K) by Arhenius law is given by

Accepted Answer

$${	ext{K}}\alpha {{	ext{e}}^{ - \frac{{	ext{E}}}{{{	ext{RT}}}}}}$$

Answer

$${	ext{K}}\alpha {{	ext{e}}^{\frac{{	ext{E}}}{{{	ext{RT}}}}}}$$

Answer

$${	ext{K}}\alpha {	ext{T}}{	ext{.}}{{	ext{e}}^{ - \frac{{	ext{E}}}{{{	ext{RT}}}}}}$$

Answer

$${	ext{K}}\alpha \sqrt {	ext{T}} {	ext{.}}{{	ext{e}}^{ - \frac{{	ext{E}}}{{{	ext{RT}}}}}}$$

Question 6

Consider the nth order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction $$\left( {{{	ext{t}}_{\frac{1}{2}}}} ight)$$ and the initial reactant concentration (CA0) gives a straight line plot?

Accepted Answer

CA0 Vs ln $${{	ext{t}}_{\frac{1}{2}}}$$

Answer

CA0 Vs $${{	ext{t}}_{\frac{1}{2}}}$$

Answer

ln CA0 Vs $${{	ext{t}}_{\frac{1}{2}}}$$

Answer

ln CA0 Vs ln $${{	ext{t}}_{\frac{1}{2}}}$$

Question 7

For a tubular flow reactor with uniform concentration and temperature, the independent variable is

Accepted Answer

Length

Answer

Time

Answer

Diameter

Answer

None of these

Question 8

A chemical reaction, A → 3B, is conducted in a constant pressure vessel. Starting with pure A, the volume of the reaction mixture increases 3 times in 6 minutes. The fractional conversion is

Accepted Answer

1

Answer

0.33

Answer

0.5

Answer

Data insufficient, can't be predicted

Question 9

For a heterogenous catalytic reaction, A + B → C, with equimole feed of A and B, the initial rate -rA0 is invariant with total pressure. The rate controlling step is

Accepted Answer

Desorption of C

Answer

Surface $$\frac{{{{	ext{K}}_{	ext{C}}}}}{{1 + {{	ext{T}}_{	ext{S}}}}}$$ reaction between absorbed A and B in the gas phase

Answer

Surface reaction between absorbed A and absorbed B

Answer

Surface reaction between A in the gas phase and absorbed B