A first order irreversible reaction, is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors.

both the conversion as well as concentrations will be different

both conversion as well as concentration are same

conversion in both will be the same but concentrations will be different

both the conversion as well as concentrations will be different

During manufacture of HSO, the oxidation of SO to SO by oxygen is an en-dothermic reaction. The yield of SO will be maximised, if the

temperature is increased and pressure is reduced.

temperature is reduced and pressure is increased.

Pick the WRONG design guideline for a reactor in which the reactions, (desired) and (undesired) are to take place. The ratio of the reaction rates is .

use batch reactor or plug flow reactor, when a > b.

use high pressure and eliminate inerts, when a > b.

use batch reactor or plug flow reactor, when a > b.

use CSTR with a high conversion, when a > b.

Considering the endotheomic dissociation of CaCO in a closed vessel (CaCO CaO + CO), the pressure of CO increases, if

an inert gas is pumped keeping the temperature constant.

If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is

unpredictable as ΔG is no measure of feasibility of a reaction.

The extent of a reaction is

different for reactants and products.

depends on the stoichiometric co-efficient.

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.

The experimentally determined overall order of the reaction, + + , is two. Then the

molecularity of the reaction is 2, but the reaction may not be elementary.

reaction is elementary with a molecularity of 2.

molecularity of the reaction is 2, but the reaction may not be elementary.

reaction may be elementary with molecularity of 2.

reaction is elementary but the molecularity may not be 2.

In a continuous flow stirred tank reactor, the composition of the exit stream

is different than that in the reactor.

is same as that in the reactor.

is different than that in the reactor.

depends upon the flow rate of inlet stream.

1443 + Mcqs in Chemical Reaction Engineering in Chemical Engineering Page 1 McqOptions

1.	The fractional volume change of the system for the isothermal gas phase reaction, 3 , between no conversion and complete conversion is
A.	0.5
B.	1
C.	2
D.	3
Answer» D. 3

Discussion

2.	What is the order of a chemical reaction, , if the rate of formation of '', increases by a factor of 2.82 on doubling the concentration of '' and increases by a factor of 9 on trebling the concentration of ''?
A.	7/2
B.	7/4
C.	5/2
D.	5/4
Answer» B. 7/4

Discussion

3.	'' plug flow reactors in series with a total volume '' gives the same conversion as a single plug flow reactor of volume '' for __________ order reactions.
A.	first
B.	second
C.	third
D.	any
Answer» E.

Discussion

4.	6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant ?
A.	100%
B.	95%
C.	75%
D.	20%
Answer» C. 75%

Discussion

5.	Fractional conversion __________ with increase in pressure for ammonia synthesis reaction ., N + 3H 2NH.
A.	increases
B.	decreases
C.	remains unchanged
D.	unpredictable from the data
Answer» B. decreases

Discussion

6.	The dimensions of rate constant for reaction 3 are (l/gm mole)/min. Therefore the reaction order is
A.	0
B.	1
C.	2
D.	3
Answer» D. 3

Discussion

7.	Reaction rate equation for the reaction, . If at is present in large excess, what is the order of this reaction?
A.	zero
B.	one
C.	two
D.	three
Answer» C. two

Discussion

8.	A first order irreversible reaction, is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors.
A.	both conversion as well as concentration are same
B.	conversion in both will be the same but concentrations will be different
C.	both the conversion as well as concentrations will be different
D.	none of these.
Answer» C. both the conversion as well as concentrations will be different

Discussion

9.	Rate of a gaseous phase reaction is given by, . The unit of rate constant is
A.	(atm)
B.	(hr)
C.	(atm)
D.	.(hr)
E.	atm.(hr)
Answer» D. .(hr)

Discussion

10.	The rate of the chemical reaction doubles as the concentration of .., is doubled. If rate of reaction is proportional to , then what is the value of for this reaction ?
A.	0.5
B.	1
C.	0
D.	2
Answer» C. 0

Discussion

11.	In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO to SO is accomplished by a __________ reaction.
A.	non-catalytic homogeneous
B.	non-catalytic heterogeneous
C.	catalytic homogenous
D.	catalytic heterogeneous
Answer» D. catalytic heterogeneous

Discussion

12.	The response curve for a step input signal from a reactor is called -curve. The variance of -curve in a 'tanks in series model' comprising of '' tanks is equal to
A.	1/
Answer» C.

Discussion

13.	Half life period of a first order irreversible reaction is
A.	/2
B.	ln
C.	/2
D.	ln 2/
E.	ln 0.5/
Answer» D. ln 2/

Discussion

14.	For the reaction , the rate of formation of is 0.2 gm mole/litre.hr. what is the rate of disappearance of in gm mole/litre. hr ?
A.	0.4
B.	0.1
C.	0.2
D.	none ofthese
Answer» B. 0.1

Discussion

15.	An irreversible aqueous phase reaction, + , is carried out in an adiabatic mixed flow reactor. A feed containing 4kmole/m of each A and B enters the reactor at 8m /hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed?Data: Heat of reaction = - 50 kJ/moleDensity of the reacting mixture = 1000kg/mSpecific heat of reacting mixture = 2kJ/kg.K The above data can be assumed to be independent of temperature and composition.
A.	190
B.	290
C.	390
D.	490
Answer» C. 390

Discussion

16.	A first order reaction occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of 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» B. reaction.

Discussion

17.	Molecularity of an elementary reaction, + + is
A.	1
B.	2
C.	3
D.	4
Answer» E.

Discussion

18.	During manufacture of HSO, the oxidation of SO to SO by oxygen is an en-dothermic reaction. The yield of SO will be maximised, if the
A.	temperature is increased.
B.	pressure is reduced.
C.	temperature is increased and pressure is reduced.
D.	temperature is reduced and pressure is increased.
Answer» E.

Discussion

19.	The vessel dispersion number (/μ) for plug flow is
A.	0
B.	500
C.	750
D.	∞
Answer» B. 500

Discussion

20.	The equilibrium constant for the reversible reaction, , is affected by the
A.	temperature of the system.
B.	presence or absence of inerts.
C.	pressure of the system.
D.	kinetics of the reaction.
Answer» D. kinetics of the reaction.

Discussion

21.	When the reaction is dominated by in-traparticle diffusion, the apparent order of reaction () as measured is related to the true order () as
A.	=
B.	+ 1
C.	none of these
Answer» B. + 1

Discussion

22.	From Arhenius law, a plot of log versus 1/ gives a straight line with a slope of (-/). The unit of / is
A.	k cal
B.	k cal/°
C.	°
D.	k cal. °
Answer» D. k cal. °

Discussion

23.	In the converter of the contact process for the manufacture of HSO the equilibrium conversion of SO __________ (A) __________ with increase in temperature and __________ (B) __________ with increase in the mole ratio of SO to air.
A.	(A) increases (B) decreases
B.	(A) decreases (B) increases
C.	(A) increases (B) increases
D.	(A) decreases (B) decreases
Answer» C. (A) increases (B) increases

Discussion

24.	For the irreversible elementary first order reaction in parallel . , a plot of . will give a straight line having a slope of
A.	/
B.	/
C.	.
D.	+
Answer» C. .

Discussion

25.	Pick the WRONG design guideline for a reactor in which the reactions, (desired) and (undesired) are to take place. The ratio of the reaction rates is .
A.	use high pressure and eliminate inerts, when a > b.
B.	avoid recycle, when a > b.
C.	use batch reactor or plug flow reactor, when a > b.
D.	use CSTR with a high conversion, when a > b.
Answer» C. use batch reactor or plug flow reactor, when a > b.

Discussion

26.	A multiple reaction may be classified as a __________ reaction.
A.	consecutive or side
B.	parallel or side
C.	mixed
D.	all (a), (b) and (c)
Answer» E.

Discussion

27.	In case of a consecutive unimolecular type first order reaction , the concentration of component __________ increases continuously with time.
A.	none of these
Answer» B.

Discussion

28.	Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme used for food digestion is present in
A.	blood
B.	saliva
C.	intestine
D.	gland
Answer» C. intestine

Discussion

29.	Considering the endotheomic dissociation of CaCO in a closed vessel (CaCO CaO + CO), the pressure of CO increases, if
A.	a catalyst is added.
B.	the temperature is increased.
C.	an inert gas is pumped keeping the temperature constant.
D.	none of these.
Answer» C. an inert gas is pumped keeping the temperature constant.

Discussion

30.	The rate of a gas phase reaction is given by . . . If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times.
A.	4
B.	16
C.	8
D.	2
Answer» C. 8

Discussion

31.	If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is
A.	not feasible.
B.	just feasible.
C.	very much feasible.
D.	unpredictable as ΔG is no measure of feasibility of a reaction.
Answer» D. unpredictable as ΔG is no measure of feasibility of a reaction.

Discussion

32.	An isothermal aqueous phase reversible reaction, , is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m .h is given by, = 0.5 - 0.125. A stream containing only enters the reactor. The residence time required (in hours) for 40% conversion of is
A.	0.80
B.	1.33
C.	1.60
D.	2.67
Answer» D. 2.67

Discussion

33.	Volume change for unimolecular type first order reaction , increases __________ with time.
A.	linearly
B.	exponentially
C.	parabolically
D.	logarithmically
Answer» C. parabolically

Discussion

34.	Half life period of decomposition of a liquid '' by irreversible first order reaction is 12 minutes. The time required for 75% conversion of '' is __________ minutes.
A.	18
B.	24
C.	6
D.	12
Answer» C. 6

Discussion

35.	The order of the reaction, , is
A.	0
B.	1
C.	2
D.	3
Answer» B. 1

Discussion

36.	The extent of a reaction is
A.	different for reactants and products.
B.	dimensionless.
C.	depends on the stoichiometric co-efficient.
D.	all of the above.
Answer» E.

Discussion

37.	The point selectivity of the product '' in the reaction, is equal to
A.	/
B.	/
C.	-
D.	-
Answer» B. /

Discussion

38.	In case of calcination of limestone, CaCO3 CaO + CO, the addition of more of CaO will result in __________ in the concentration of CO.
A.	no change
B.	increase
C.	decrease
D.	unpredictable from the data
Answer» B. increase

Discussion

39.	For the chemical reaction , it is observed that, on doubling the concentration of '', the reaction rate quadruples. If the reaction rate is proportional to , then what is the value of '' ?
A.	4
B.	1/4
C.	16
D.	2
Answer» B. 1/4

Discussion

40.	For a __________ order chemical reaction, , the half life period is independent of the initial concentration of the reactant .
A.	zero
B.	first
C.	second
D.	third
Answer» C. second

Discussion

41.	The rate expression for the gaseous phase reaction, CO + 2H CHOH, is given by, . Which of the following is not possible ?
A.	α = 1, β = 1, γ =1
B.	α = 1, β = 2, γ = 1
C.	α = 1/3, β = 2/3, γ = 1/3
D.	α = 1/2, β = 1, γ = 1/2
Answer» B. α = 1, β = 2, γ = 1

Discussion

42.	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.

Discussion

43.	The experimentally determined overall order of the reaction, + + , is two. Then the
A.	reaction is elementary with a molecularity of 2.
B.	molecularity of the reaction is 2, but the reaction may not be elementary.
C.	reaction may be elementary with molecularity of 2.
D.	reaction is elementary but the molecularity may not be 2.
Answer» B. molecularity of the reaction is 2, but the reaction may not be elementary.

Discussion

44.	In a continuous flow stirred tank reactor, the composition of the exit stream
A.	is same as that in the reactor.
B.	is different than that in the reactor.
C.	depends upon the flow rate of inlet stream.
D.	none of these.
Answer» B. is different than that in the reactor.

Discussion

45.	Reaction rate of a first order reaction, which is half completed in 23 minutes will be
A.	0.03 sec
B.	0.03 min
C.	0.03 hr
D.	0.05 min
Answer» C. 0.03 hr

Discussion

46.	The half life period 't' of a zero order reaction, , is equal to
A.	/2
B.	/
C.	0.693/
D.	1/
Answer» B. /

Discussion

47.	The conversion for a first order liquid phase reaction. 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
A.	60
B.	75
C.	90
D.	100
Answer» C. 90

Discussion

48.	In the hydrodealkylation of toluene to benzene, the following reactions occur:CH + H CH + CH2CH CH + HToluene and hydrogen are fed to a reactor in a molar ratio 1:5.80% of the toluene gets converted and the selectivity of benzene(defined as moles of benzene formed/moles of toluene converted) is 90%. The fractional conversion of hydrogen is
A.	0.16
B.	0.144
C.	0.152
D.	0.136
Answer» C. 0.152

Discussion

49.	Equilibrium of a chemical reaction as viewed by kinetics is a __________ state.
A.	dynamic steady
B.	static steady
C.	dynamic unsteady
D.	none of these
Answer» B. static steady

Discussion

50.	The conversion in a mixed reactor/accomplishing a reaction 3 is 50% when gaseous reactant '' 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

Discussion

Explore topic-wise MCQs in Chemical Engineering.

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

What is the order of a chemical reaction, , if the rate of formation of '', increases by a factor of 2.82 on doubling the concentration of '' and increases by a factor of 9 on trebling the concentration of ''?

'' plug flow reactors in series with a total volume '' gives the same conversion as a single plug flow reactor of volume '' for __________ order reactions.

6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant ?

Fractional conversion __________ with increase in pressure for ammonia synthesis reaction ., N + 3H 2NH.

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

Reaction rate equation for the reaction, . If at is present in large excess, what is the order of this reaction?

A first order irreversible reaction, is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors.

Rate of a gaseous phase reaction is given by, . The unit of rate constant is

The rate of the chemical reaction doubles as the concentration of .., is doubled. If rate of reaction is proportional to , then what is the value of for this reaction ?

In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO to SO is accomplished by a __________ reaction.

The response curve for a step input signal from a reactor is called -curve. The variance of -curve in a 'tanks in series model' comprising of '' tanks is equal to

Half life period of a first order irreversible reaction is

For the reaction , the rate of formation of is 0.2 gm mole/litre.hr. what is the rate of disappearance of in gm mole/litre. hr ?

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

Molecularity of an elementary reaction, + + is

During manufacture of HSO, the oxidation of SO to SO by oxygen is an en-dothermic reaction. The yield of SO will be maximised, if the

The vessel dispersion number (/μ) for plug flow is

The equilibrium constant for the reversible reaction, , is affected by the

When the reaction is dominated by in-traparticle diffusion, the apparent order of reaction () as measured is related to the true order () as

From Arhenius law, a plot of log versus 1/ gives a straight line with a slope of (-/). The unit of / is

In the converter of the contact process for the manufacture of HSO the equilibrium conversion of SO __________ (A) __________ with increase in temperature and __________ (B) __________ with increase in the mole ratio of SO to air.

For the irreversible elementary first order reaction in parallel . , a plot of . will give a straight line having a slope of

Pick the WRONG design guideline for a reactor in which the reactions, (desired) and (undesired) are to take place. The ratio of the reaction rates is .

A multiple reaction may be classified as a __________ reaction.

In case of a consecutive unimolecular type first order reaction , the concentration of component __________ increases continuously with time.

Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme used for food digestion is present in

Considering the endotheomic dissociation of CaCO in a closed vessel (CaCO CaO + CO), the pressure of CO increases, if

The rate of a gas phase reaction is given by . . . If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times.

If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is

An isothermal aqueous phase reversible reaction, , is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m .h is given by, = 0.5 - 0.125. A stream containing only enters the reactor. The residence time required (in hours) for 40% conversion of is

Volume change for unimolecular type first order reaction , increases __________ with time.

Half life period of decomposition of a liquid '' by irreversible first order reaction is 12 minutes. The time required for 75% conversion of '' is __________ minutes.

The order of the reaction, , is

The extent of a reaction is

The point selectivity of the product '' in the reaction, is equal to

In case of calcination of limestone, CaCO3 CaO + CO, the addition of more of CaO will result in __________ in the concentration of CO.

For the chemical reaction , it is observed that, on doubling the concentration of '', the reaction rate quadruples. If the reaction rate is proportional to , then what is the value of '' ?

For a __________ order chemical reaction, , the half life period is independent of the initial concentration of the reactant .

The rate expression for the gaseous phase reaction, CO + 2H CHOH, is given by, . Which of the following is not possible ?

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

The experimentally determined overall order of the reaction, + + , is two. Then the

In a continuous flow stirred tank reactor, the composition of the exit stream

Reaction rate of a first order reaction, which is half completed in 23 minutes will be

The half life period 't' of a zero order reaction, , is equal to

The conversion for a first order liquid phase reaction. 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

Equilibrium of a chemical reaction as viewed by kinetics is a __________ state.

The conversion in a mixed reactor/accomplishing a reaction 3 is 50% when gaseous reactant '' 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.

In the converter of the contact process for the manufacture of HSO the equilibrium conversion of SO (A) with increase in temperature and (B) with increase in the mole ratio of SO to air.