Chemical Reaction Engineering

Question: A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?
[A].

Inner catalyst core of radius R/8 does not participate in reaction.

[B].

Inner catalyst core of radius R/2 does not participate in reaction.

[C].

Inner catalyst core of radius 7R/8 does not participate in reaction.

[D].

Effectiveness factor for a zero order reaction can not be 7/8 as it must always be 1.

Answer: Option A

Explanation:

No answer description available for this question.

Question: For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the
[A].

catalyst size is reduced or the catalyst diffusivity is reduced.

[B].

catalyst size is reduced or the catalyst diffusivity is increased.

[C].

catalyst size is increased or the catalyst diffusivity is reduced.

[D].

catalyst size is increased or the catalyst diffusivity is increased.

Answer: Option B

Explanation:

No answer description available for this question.

Question: A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length
[A].

decreases.

[B].

increases.

[C].

is at the highest allowable temperature throughout.

[D].

first increases and then decreases.

Answer: Option C

Explanation:

No answer description available for this question.

Question: An example of autothermal reactor operation is
[A].

sulphur dioxide oxidation

[B].

ethylene oxidation

[C].

benzene oxidation

[D].

ammonia synthesis

Answer: Option B

Explanation:

No answer description available for this question.

Question: A typical example of an exothermic reversible reaction conducted at high pressure in industry is
[A].

dehydration of ethanol.

[B].

methanol synthesis.

[C].

reformation of methane.

[D].

polymerisation of ethylene.

Answer: Option A

Explanation:

No answer description available for this question.

Question: 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
[A].

surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase.

[B].

surface reaction between absorbed A and absorbed B.

[C].

surface reaction between A in the gas phase and absorbed B.

[D].

desorption of C.

Answer: Option D

Explanation:

No answer description available for this question.

Question: Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17the KP for the reaction CO + H2O = CO2 + H2 is
[A].

103.01

[B].

10-0.67

[C].

10-3.01

[D].

l00.67

Answer: Option D

Explanation:

No answer description available for this question.

Question: If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to
[A].

the intrinsic activation energy E.

[B].

(E + ED) where ED is activation due to diffusion.

[C].

(E + ED)/2

[D].

ED/2

Answer: Option D

Explanation:

No answer description available for this question.

Question: A first order reaction A B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A at the centre of the pellet is much less than at the external surface, the process is limited by
[A].

diffusion within the pellet.

[B].

reaction.

[C].

external mass transfer.

[D].

none of the above.

Answer: Option A

Explanation:

No answer description available for this question.

Question: For the gaseous reaction 2A B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is
[A].

1

[B].

-0.5

[C].

-0.25

[D].

0

Answer: Option C

Explanation:

No answer description available for this question.