In a reversible reaction, a catalyst increases the rate of forward reaction

To a greater extent than that of the backward reaction

And decreases that of the backward reaction

And the backward reaction equally

Least expensive to operate for a given rate

Suitable for gas-phase reactions on commercial scale

Suitable for liquid phase reactions involving small production rate

Least expensive to operate for a given rate

Most suitable for very large production rate

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

First increases and then decreases

Is at the highest allowable temperature throughout

First increases and then decreases

An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction:

Goes through a maximum along the length of the reactor

Is maximum at the inlet of the reactor

Goes through a maximum along the length of the reactor

Goes through a minimum along the length of the reactor

Is maximum at the exit of the reactor

Sometimes, batch process is preferred over continuous process, when the product

Quality & yield cannot be achieved in continuous processes, because of long residence time

For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor.

Fixed bed reactor followed by a fluidised

Fluidised bed reactor followed by a fixed

Fixed bed reactor followed by a fluidised

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

Slow reactions in catalyst of large pore diameter

Fast reactions in catalyst of small pore diameter

Fast reaction in catalyst of large pore diameter

Slow reactions in catalyst of small pore diameter

Slow reactions in catalyst of large pore diameter

For a heterogeneous catalytic reaction

A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important

Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction

A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important

The catalyst does not form an intermediate complex with the reactant

The surface of the catalyst does not play an important role during reaction

Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in __________ in conversion.

Either (A) or (B), depends on the type of reaction

In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3), the value of the equilibrium constant depends on the

Initial concentration of N2 and H2

The reason why a catalyst increases the rate of reaction is that, it

Increases the activation energy

Decreases the energy barrier for reaction

Increases the activation energy

Decreases the molecular collision diameter

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to

The intrinsic activation energy E

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

Measures the catalyst surface area directly

Is made entirely of stainless steel

Pick out the wrong statement:

Half life of a reaction increases with increased initial concentration for reaction orders more than one

Chemical reactions with high activation energy are very temperature sensitive

A flat velocity profile exists in a plug flow reactor

The residence time for all the elements of fluid in case of a P.F.R. need not be same

Half life of a reaction increases with increased initial concentration for reaction orders more than one

Increases the equilibrium concentration of the product

Changes the equilibrium constant of the reaction

Shortens the time to reach the equilibrium

A catalyst loses its activity due to

Loss in surface area of the active component

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

Covering of the catalytic active sites by a foreign substance

In a semi-batch reactor,

Condition similar to plug flow reactor exists

Mixing takes place in axial direction only

Velocity of reaction can be controlled

Condition similar to plug flow reactor exists

The unit of frequency factor in Arrhenius equation is

Same as that of activation energy

1443 + Mcqs in Chemical Reaction Engineering Page 24 McqOptions

1151.	Radioactive decay follows __________ order kinetics.
A.	First
B.	Second
C.	Third
D.	Zero
Answer» B. Second

1152.	In a reversible reaction, a catalyst increases the rate of forward reaction
A.	Only
B.	To a greater extent than that of the backward reaction
C.	And decreases that of the backward reaction
D.	And the backward reaction equally
Answer» E.

1153.	A batch reactor is
A.	Suitable for gas-phase reactions on commercial scale
B.	Suitable for liquid phase reactions involving small production rate
C.	Least expensive to operate for a given rate
D.	Most suitable for very large production rate
Answer» C. Least expensive to operate for a given rate

1154.	With increase in initial concentration, the fractional conversion of a first order reaction in a given time
A.	Increases
B.	Decreases
C.	Remain constant
D.	Unpredictable
Answer» D. Unpredictable

1155.	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» D. First increases and then decreases

1156.	An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction:
A.	Is maximum at the inlet of the reactor
B.	Goes through a maximum along the length of the reactor
C.	Goes through a minimum along the length of the reactor
D.	Is maximum at the exit of the reactor
Answer» B. Goes through a maximum along the length of the reactor

1157.	Sometimes, batch process is preferred over continuous process, when the product
A.	Quality & yield cannot be achieved in continuous processes, because of long residence time
B.	Sales demand is fluctuating
C.	Both (A) & (B)
D.	Neither (A) nor (B)
Answer» D. Neither (A) nor (B)

1158.	The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are
A.	2 & 1
B.	11 & 2
C.	2 & 2
D.	1 & 1
Answer» B. 11 & 2

1159.	For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor.
A.	Fixed
B.	Fluidised bed reactor followed by a fixed
C.	Fixed bed reactor followed by a fluidised
D.	Fluidised
Answer» C. Fixed bed reactor followed by a fluidised

1160.	Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature?
A.	Pore diffusion
B.	Film diffusion
C.	Ash layer diffusion
D.	Chemical reaction
Answer» C. Ash layer diffusion

1161.	In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for
A.	Fast reactions in catalyst of small pore diameter
B.	Fast reaction in catalyst of large pore diameter
C.	Slow reactions in catalyst of small pore diameter
D.	Slow reactions in catalyst of large pore diameter
Answer» D. Slow reactions in catalyst of large pore diameter

1163.	Half-life period for a first order reaction is __________ the initial concentration of the reactant.
A.	Directly proportional to
B.	Inversely proportional to
C.	Independent of
D.	None of these
Answer» D. None of these

1168.	Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the
A.	Activation energy
B.	Equilibrium constant
C.	Heat of reaction
D.	None of these
Answer» B. Equilibrium constant

1169.	Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an __________ reaction.
A.	Elementary
B.	Parallel
C.	Consecutive
D.	None of these
Answer» D. None of these

1170.	The eddy diffusivity for a liquid in plug flow must be
A.	1
B.	0
C.	∞
D.	Between 0 and 1
Answer» C. ∞

1162.	For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is:
A.	2
B.	4
C.	11
D.	22
Answer» D. 22

1164.	For a heterogeneous catalytic reaction
A.	Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction
B.	A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important
C.	The catalyst does not form an intermediate complex with the reactant
D.	The surface of the catalyst does not play an important role during reaction
Answer» B. A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important

1165.	Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in __________ in conversion.
A.	Decrease
B.	Increase
C.	No change
D.	Either (A) or (B), depends on the type of reaction
Answer» D. Either (A) or (B), depends on the type of reaction

1166.	In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3), the value of the equilibrium constant depends on the
A.	Total pressure of the system
B.	Volume of the reactor
C.	Temperature
D.	Initial concentration of N2 and H2
Answer» D. Initial concentration of N2 and H2

1167.	In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same.
A.	Semi-batch
B.	Tubular
C.	Batch
D.	Back-mix
Answer» E.

1171.	There is no correspondence between stoichiometric and the rate equation in case of a/an __________ reaction.
A.	Elementary
B.	Multiple
C.	Autocatalytic
D.	Non-elementary
Answer» E.

1172.	In which of the following gaseous phase reversible reactions, the product yield cannot be increased by the application of high pressure?
A.	N2 + O2 ⇌ 2NO
B.	PCl3 + Cl2 ⇌ PCl5
C.	N + 3H2 ⇌ 2NH3
D.	2SO2 + O2 ⇌ 2SO3
Answer» B. PCl3 + Cl2 ⇌ PCl5

1173.	The reason why a catalyst increases the rate of reaction is that, it
A.	Decreases the energy barrier for reaction
B.	Increases the activation energy
C.	Decreases the molecular collision diameter
D.	None of these
Answer» B. Increases the activation energy

1174.	In a/an __________ vessel, the fluid enters and leaves following plug flow
A.	Open
B.	Closed
C.	Open-closed
D.	Close-opened
Answer» C. Open-closed

1175.	The half life period of a first order reaction is given by (where, K = rate constant.)
A.	1.5 K
B.	2.5 K
C.	0.693/K
D.	6.93 K
Answer» D. 6.93 K

Explore topic-wise MCQs in Chemical Engineering.

Radioactive decay follows __________ order kinetics.

In a reversible reaction, a catalyst increases the rate of forward reaction

A batch reactor is

With increase in initial concentration, the fractional conversion of a first order reaction in a given time

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

An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction:

Sometimes, batch process is preferred over continuous process, when the product

The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are

For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor.

Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature?

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

For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is:

Half-life period for a first order reaction is __________ the initial concentration of the reactant.

For a heterogeneous catalytic reaction

Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in __________ in conversion.

In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3), the value of the equilibrium constant depends on the

In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same.

Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the

Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an __________ reaction.

The eddy diffusivity for a liquid in plug flow must be

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

In which of the following gaseous phase reversible reactions, the product yield cannot be increased by the application of high pressure?

The reason why a catalyst increases the rate of reaction is that, it

In a/an __________ vessel, the fluid enters and leaves following plug flow

The half life period of a first order reaction is given by (where, K = rate constant.)

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to

BET apparatus

When an exothermic reversible reaction is conducted adiabatically, the rate of reaction

Pick out the wrong statement:

Reactions with high activation energy are

In an exothermic chemical reaction, the reactants compared to the products have

The conversion in a mixed reactor/accomplishing a reaction A → 3R is 50% when gaseous reactant 'A' is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is __________ second.

If CA is the quantity of reactants initially present, the quantity left after 'n' half periods will be equal to

A Catalyst

The rate constant of a chemical reaction decreases by decreasing the

For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of 'P' is doubled. If the reaction rate is proportional to Cp n , then what is the value of 'n' for this chemical reaction?

With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion).

The fractional volume change of the system for the isothermal gas phase reaction, A → 3B, between no conversion and complete conversion is

The dimensions of rate constant for reaction 3A → B are (l/gm mole)/min. Therefore the reaction order is

What is the dispersion number for a plug flow reactor?

A catalyst loses its activity due to

In a semi-batch reactor,

In case of a/an __________ chemical reaction, conversion increases with the rise in temperature.

If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the

If the time required for half change is inversely proportional to the square of initial concentration and the velocity depends on the units in which the concentration term is expressed, then the order of reaction is

The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called

The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is

From collision theory, the reaction rate constant is proportional to

A batch adiabatic reactor at an initial temperature of 373°K is being used for the reaction, A → B. Assume the heat of reaction is - 1kJ/mole at 373°K and heat capacity of both A and B to be constant and equal to 50J/mole.K. The temperature rise after a conversion of 0.5 will be:

The unit of frequency factor in Arrhenius equation is

1176.	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» E.

1177.	BET apparatus
A.	Measures the catalyst surface area directly
B.	Operates at very high pressure
C.	Is made entirely of stainless steel
D.	None of these
Answer» E.

1178.	When an exothermic reversible reaction is conducted adiabatically, the rate of reaction
A.	Continuously increases
B.	Continuously decreases
C.	Passes through a maximum
D.	Passes through a minimum
Answer» D. Passes through a minimum

1179.	Pick out the wrong statement:
A.	Chemical reactions with high activation energy are very temperature sensitive
B.	A flat velocity profile exists in a plug flow reactor
C.	The residence time for all the elements of fluid in case of a P.F.R. need not be same
D.	Half life of a reaction increases with increased initial concentration for reaction orders more than one
Answer» D. Half life of a reaction increases with increased initial concentration for reaction orders more than one

1180.	Reactions with high activation energy are
A.	Very temperature sensitive
B.	Temperature insensitive
C.	Always irreversible
D.	Always reversible
Answer» B. Temperature insensitive

1181.	In an exothermic chemical reaction, the reactants compared to the products have
A.	Higher temperature
B.	More energy
C.	Less energy
D.	Same energy
Answer» C. Less energy

1182.	The conversion in a mixed reactor/accomplishing a reaction A → 3R is 50% when gaseous reactant 'A' is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is __________ second.
A.	0.5
B.	1
C.	2
D.	3
Answer» B. 1

1183.	If CA is the quantity of reactants initially present, the quantity left after 'n' half periods will be equal to
A.	(CA/2)n
B.	(½) n CA
C.	(CA/2)1/n
D.	(CA) 1/2n
Answer» C. (CA/2)1/n

1184.	A Catalyst
A.	Increases the equilibrium concentration of the product
B.	Changes the equilibrium constant of the reaction
C.	Shortens the time to reach the equilibrium
D.	None of these
Answer» D. None of these

1185.	The rate constant of a chemical reaction decreases by decreasing the
A.	Pressure
B.	Concentration of reactants
C.	Temperature
D.	Duration of reaction
Answer» D. Duration of reaction