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

The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the_________________?

Increased temperature reduces the activation energy

Fraction of molecules having threshold energy increases

Value of threshold energy decreases

The reaction rate constants at two different temperatures T1 and T2 are related by _________________?

exp (k2/k1) = (E/R) (1/T2 – 1/T1)

ln (k2/k1) = (E/R) (1/T2 – 1/T1)

ln (k2/k1) = (E/R) (1/T1 – 1/T2)

exp (k2/k1) = (E/R) (1/T2 – 1/T1)

exp (k2/k1) = (E/R) (1/T1 – 1/T2)

The reactions of high molecularity are rare, because________________?

Many body collisions are not favoured energetically

Of very large activation energy of many bodies

Of low probability of many body collisions

Many body collisions are not favoured energetically

Of requirement of very large concentration for such reactions

The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?

Surface reaction between A in the gas phase and absorbed B

Surface reaction between absorbed A and absorbed B

Surface reaction between absorbed A and B in the gas phase

Surface reaction between A in the gas phase and absorbed B

The rate of an autocatalytic reaction as shown in the bellow figure, is given by – rA = k . CA . CB. In this case, the__________________?

Plot of – rA Vs CA is a straight line with slope k

Plot of – rA Vs CA is a hyperbola

Rate of disappearance of reactant A is maximum, where CA = CB

The rate of a homogeneous reaction is a function of__________________?

Temperature and composition only

All temperature, pressure and composition

The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, KA, KB and KC are the equilibrium constants and is the rate constant of the rate controlling step) ?

k KAKB pApB / (1 + KApA + KBpB)

k KAKB pApB / (1 + KApA + KBpB + KCpC)

k KAKB pApB / (1 + KApA + KBpB + KCpC)2

The rate constant of a reaction is a function of the ___________________?

Initial concentration of the reactants

The rate constant of a reaction depends on the __________________?

Initial concentration of reactants

The preferred reacting system for oxidation of o-xylene to phthalic anhydride is _____________________?

Jacketed steam heated multitubular reactor

Multitubular reactor with cooling

Multistage multitubular reactor with interstage cooling

The order of a chemical reaction is__________________?

Always equal to the total stoichiometric number of reactants

An experimentally determined quantity

Always equal to the total stoichiometric number of reactants

The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the_________________?

Space time for parallel lines is different

Space time for each parallel line is same

Space time for parallel lines is different

Larger reactors have more space time compared to smaller ones

The minimum energy required to allow a chemical reaction to proceed is termed as the ‘threshold energy ‘. Chemical reactions with low activation energy are ________________?

Insensitive to temperature changes

The irreversible reaction, X → Y, is the special case of the reversible reaction, X ⇌ Y, in which the _____________________?

Equilibrium constant is infinite

Fractional conversion of ‘A’ at equilibrium is unity

Concentration of ‘A’ at equilibrium is zero

The irreversible reaction is a special case of reversible reaction, if the________________?

Conversion of the reactant at equilibrium condition is zero

Reactant concentration at equilibrium condition is zero

The increase in the rate of reaction with temperature is due to__________________?

Increase in the average kinetic energy of the reacting molecules

Increase in the number of effective collisions

Increase in the average kinetic energy of the reacting molecules

The importance of diffusion in a catalyst are increased by ____________________?

An active surface of the catalyst

409 + Mcqs in Chemical Reaction in Chemical Engineering Page 2 McqOptions

51.	The sequence in which three CSTR’s of volumes 5, 10 and 15 m3 will be connected in series to obtain the maximum production in a second order irreversible reaction is ____________________?
A.	15, 10, 5
B.	5, 10, 15
C.	10, 5, 15
D.	10, 15, 5
Answer» B. 5, 10, 15

Discussion

52.	The role of a catalyst in a chemical reaction is to change the__________________?
A.	Equilibrium constant
B.	Activation energy
C.	Final products
D.	Heat of reaction
Answer» C. Final products

Discussion

53.	The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a ‘tanks in series model’ comprising of ‘m’ tanks is equal to ___________________?
A.	m
B.	1/m
C.	√m
D.	m2
Answer» C. √m

Discussion

54.	The residence time distribution of an ideal CSTR is _____________________?
A.	(1/η) exp (-t/η)
B.	η exp (-t/η)
C.	exp (-t/η)
D.	(1/η) (-t/η)
Answer» D. (1/η) (-t/η)

Discussion

55.	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

Discussion

56.	The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the_________________?
A.	Increased temperature reduces the activation energy
B.	Fraction of molecules having threshold energy increases
C.	Collision frequency increases
D.	Value of threshold energy decreases
Answer» C. Collision frequency increases

Discussion

57.	The reaction rate constants at two different temperatures T1 and T2 are related by _________________?
A.	ln (k2/k1) = (E/R) (1/T2 – 1/T1)
B.	ln (k2/k1) = (E/R) (1/T1 – 1/T2)
C.	exp (k2/k1) = (E/R) (1/T2 – 1/T1)
D.	exp (k2/k1) = (E/R) (1/T1 – 1/T2)
Answer» C. exp (k2/k1) = (E/R) (1/T2 – 1/T1)

Discussion

58.	The reactions with low activation energy are _____________________?
A.	Always spontaneous
B.	Slow
C.	Fast
D.	Non-spontaneous
Answer» D. Non-spontaneous

Discussion

59.	The reactions of high molecularity are rare, because________________?
A.	Of very large activation energy of many bodies
B.	Of low probability of many body collisions
C.	Many body collisions are not favoured energetically
D.	Of requirement of very large concentration for such reactions
Answer» C. Many body collisions are not favoured energetically

Discussion

60.	The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an _______________ reaction?
A.	Elementary
B.	Non-elementary
C.	Parallel
D.	Autokinetic
Answer» B. Non-elementary

Discussion

61.	The reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
A.	Biochemical
B.	Photochemical
C.	Catalytic
D.	Autocatalytic
Answer» E.

Discussion

62.	The reaction between oxygen and organic material is a/an _____________ reaction?
A.	Exothermic
B.	Endothermic
C.	Biochemical
D.	Photochemical
Answer» B. Endothermic

Discussion

63.	The reaction A → B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is __________________?
A.	0
B.	1
C.	1.5
D.	2
Answer» B. 1

Discussion

64.	The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k) is (Data: Heat of reaction at 298 K = – 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature)) ?
A.	400
B.	500
C.	600
D.	1000
Answer» D. 1000

Discussion

65.	The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is________________?
A.	∞
B.	0
C.	1
D.	> 1
Answer» D. > 1

Discussion

66.	The ratio of moles of a reactant converted into the desired product to that converted into unwanted product is called_________________?
A.	Operational yield
B.	Relative yield
C.	Selectivity
D.	None of these
Answer» D. None of these

Discussion

67.	The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?
A.	Absorption of A
B.	Surface reaction between absorbed A and absorbed B
C.	Surface reaction between absorbed A and B in the gas phase
D.	Surface reaction between A in the gas phase and absorbed B
Answer» D. Surface reaction between A in the gas phase and absorbed B

Discussion

68.	The rate of the reaction, X → Y, quadruples when the concentration of ‘X’ is doubled. The rate expression for the reaction is, r = K Cx n, the value of ‘n’ in this case will be_______________________?
A.	0
B.	1
C.	2
D.	3
Answer» D. 3

Discussion

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

Discussion

70.	The rate of reaction of a/an ______________ reaction is not affected by temperature rise ?
A.	Autocatalytic
B.	Photochemical
C.	Consecutive
D.	Zero order
Answer» C. Consecutive

Discussion

71.	The rate of reaction does not decrease appreciably as the reaction proceeds in case of ______________ reactions?
A.	Autocatalytic
B.	Exothermic
C.	Endothermic
D.	Autothermal
Answer» B. Exothermic

Discussion

72.	The rate of forward reaction, at chemical equilibrium is ______________ the rate of backward reaction?
A.	More than
B.	Less than
C.	Equal to
D.	Either B. or C.
Answer» D. Either B. or C.

Discussion

73.	The rate of an autocatalytic reaction as shown in the bellow figure, is given by – rA = k . CA . CB. In this case, the__________________?
A.	Plot of – rA Vs CA is a straight line with slope k
B.	Plot of – rA Vs CA is a hyperbola
C.	Rate of disappearance of reactant A is maximum, where CA = CB
D.	Both B & C
Answer» E.

Discussion

74.	The rate of a homogeneous reaction is a function of__________________?
A.	Temperature and pressure only
B.	Temperature and composition only
C.	Pressure and composition only
D.	All temperature, pressure and composition
Answer» E.

Discussion

75.	The rate of a chemical reaction is almost doubled for every 10°C rise in temperature. The rate will increase ______________ times, if the temperature rises from 10 to 100°C?
A.	256
B.	512
C.	112
D.	612
Answer» C. 112

Discussion

76.	The rate of a gas phase reaction is given by K . CA . CB. 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

77.	The rate expression for a heterogeneous catalytic reaction is given by, – rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A) ?
A.	E
B.	E + ΔHA
C.	E + ΔHA – ΔHR)
D.	ΔHA + ΔHR
Answer» D. ΔHA + ΔHR

Discussion

78.	The rate equation for the reaction represented by as shown in the bellow figure, is given by – rx = K1 . Cx/(1 + K2 Cx). At high value of Cx (i.e.., K2Cx > > 1), the order of the reaction and the rate constant are respectively___________________?
A.	Zero order & K1/K2
B.	Zero order & K1
C.	First order & K1
D.	First order & K1/K2
Answer» B. Zero order & K1

Discussion

79.	The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, KA, KB and KC are the equilibrium constants and is the rate constant of the rate controlling step) ?
A.	k KA pApB / (1 + KApA + KBpB)
B.	k KAKB pApB / (1 + KApA + KBpB)
C.	k KAKB pApB / (1 + KApA + KBpB + KCpC)
D.	k KAKB pApB / (1 + KApA + KBpB + KCpC)2
Answer» E.

Discussion

80.	The rate constant of a reaction is a function of the ___________________?
A.	Time of reaction
B.	Temperature of the system
C.	Extent of reaction
D.	Initial concentration of the reactants
Answer» C. Extent of reaction

Discussion

81.	The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of „E/R’ is __________________?
A.	8987°K
B.	9210°K
C.	8764°K
D.	8621°K
Answer» C. 8764°K

Discussion

82.	The rate constant of a reaction depends on the __________________?
A.	Initial concentration of reactants
B.	Time of reaction
C.	Temperature of the system
D.	Extent of reaction
Answer» D. Extent of reaction

Discussion

83.	The rate constant of a chemical reaction increases by increasing the______________________?
A.	Temperature
B.	Pressure
C.	Reactant’s concentration
D.	None of these
Answer» B. Pressure

Discussion

84.	The rate constant of a first order reaction depends on the ________________?
A.	Concentration of the reactant
B.	Temperature
C.	Concentration of the product
D.	Time
Answer» C. Concentration of the product

Discussion

85.	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

Discussion

86.	The rate at which a chemical substance reacts is proportional to its____________________?
A.	Active mass
B.	Equivalent weight
C.	Molecular weight
D.	None of these
Answer» B. Equivalent weight

Discussion

87.	The rate at which a chemical substance reacts is proportional to its _____________________?
A.	Active mass
B.	Molecular weight
C.	Equivalent weight
D.	Atomic weight
Answer» B. Molecular weight

Discussion

88.	The preferred reacting system for oxidation of o-xylene to phthalic anhydride is _____________________?
A.	Jacketed liquid phase CSTR
B.	Jacketed steam heated multitubular reactor
C.	Multitubular reactor with cooling
D.	Multistage multitubular reactor with interstage cooling
Answer» B. Jacketed steam heated multitubular reactor

Discussion

89.	The performance of a cascade of CSTR’s can be improved by adding__________________?
A.	A P.F. reactor in series
B.	A P.F. reactor in parallel
C.	More CSTR’s in series
D.	More CSTR’s in parallel
Answer» D. More CSTR’s in parallel

Discussion

90.	The order of the chemical reaction as shown in the bellow figure, whose rate equation is given as -rA = KCA_________________?
A.	0
B.	1
C.	2
D.	3
Answer» E.

Discussion

91.	The order of a chemical reaction is__________________?
A.	An experimentally determined quantity
B.	Always equal to the total stoichiometric number of reactants
C.	Never fractional
D.	None of these
Answer» B. Always equal to the total stoichiometric number of reactants

Discussion

92.	The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the_________________?
A.	Space time for each parallel line is same
B.	Space time for parallel lines is different
C.	Larger reactors have more space time compared to smaller ones
D.	None of these
Answer» B. Space time for parallel lines is different

Discussion

93.	The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is________________________?
A.	Backmix reactor
B.	Plug flow reactor
C.	Series of CSTR
D.	PFR in series
Answer» B. Plug flow reactor

Discussion

94.	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

Discussion

95.	The minimum energy required to allow a chemical reaction to proceed is termed as the ‘threshold energy ‘. Chemical reactions with low activation energy are ________________?
A.	Always irreversible
B.	Insensitive to temperature changes
C.	Mostly irreversible
D.	Highly temperature sensitive
Answer» C. Mostly irreversible

Discussion

96.	The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of _______________ order?
A.	Zero
B.	First
C.	Second
D.	None of these
Answer» D. None of these

Discussion

97.	The irreversible reaction, X → Y, is the special case of the reversible reaction, X ⇌ Y, in which the _____________________?
A.	Equilibrium constant is infinite
B.	Fractional conversion of ‘A’ at equilibrium is unity
C.	Concentration of ‘A’ at equilibrium is zero
D.	All A., B. and C.
Answer» E.

Discussion

98.	The irreversible reaction is a special case of reversible reaction, if the________________?
A.	Equilibrium constant is 1
B.	Conversion of the reactant at equilibrium condition is zero
C.	Reactant concentration at equilibrium condition is zero
D.	All A., B. and C.
Answer» D. All A., B. and C.

Discussion

99.	The increase in the rate of reaction with temperature is due to__________________?
A.	Increase in the number of effective collisions
B.	Decrease in activation energy
C.	Increase in the average kinetic energy of the reacting molecules
D.	None of these
Answer» C. Increase in the average kinetic energy of the reacting molecules

Discussion

100.	The importance of diffusion in a catalyst are increased by ____________________?
A.	Large catalyst particle size
B.	An active surface of the catalyst
C.	Small pore diameter
D.	All A., B. and C.
Answer» E.

Discussion

Explore topic-wise MCQs in Chemical Engineering.

The sequence in which three CSTR’s of volumes 5, 10 and 15 m3 will be connected in series to obtain the maximum production in a second order irreversible reaction is ____________________?

The role of a catalyst in a chemical reaction is to change the__________________?

The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a ‘tanks in series model’ comprising of ‘m’ tanks is equal to ___________________?

The residence time distribution of an ideal CSTR is _____________________?

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

The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the_________________?

The reaction rate constants at two different temperatures T1 and T2 are related by _________________?

The reactions with low activation energy are _____________________?

The reactions of high molecularity are rare, because________________?

The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an _______________ reaction?

The reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?

The reaction between oxygen and organic material is a/an _____________ reaction?

The reaction A → B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is __________________?

The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is________________?

The ratio of moles of a reactant converted into the desired product to that converted into unwanted product is called_________________?

The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?

The rate of the reaction, X → Y, quadruples when the concentration of ‘X’ is doubled. The rate expression for the reaction is, r = K Cx n, the value of ‘n’ in this case will be_______________________?

The rate of the chemical reaction A → B doubles as the concentration of A i.e.., CA is doubled. If rate of reaction is proportional to CA n, then what is the value of n for this reaction ?

The rate of reaction of a/an ______________ reaction is not affected by temperature rise ?

The rate of reaction does not decrease appreciably as the reaction proceeds in case of ______________ reactions?

The rate of forward reaction, at chemical equilibrium is ______________ the rate of backward reaction?

The rate of an autocatalytic reaction as shown in the bellow figure, is given by – rA = k . CA . CB. In this case, the__________________?

The rate of a homogeneous reaction is a function of__________________?

The rate of a chemical reaction is almost doubled for every 10°C rise in temperature. The rate will increase ______________ times, if the temperature rises from 10 to 100°C?

The rate of a gas phase reaction is given by K . CA . CB. 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?

The rate equation for the reaction represented by as shown in the bellow figure, is given by – rx = K1 . Cx/(1 + K2 Cx). At high value of Cx (i.e.., K2Cx > > 1), the order of the reaction and the rate constant are respectively___________________?

The rate constant of a reaction is a function of the ___________________?

The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of „E/R’ is __________________?

The rate constant of a reaction depends on the __________________?

The rate constant of a chemical reaction increases by increasing the______________________?

The rate constant of a first order reaction depends on the ________________?

The rate constant of a chemical reaction decreases by decreasing the____________________?

The rate at which a chemical substance reacts is proportional to its____________________?

The rate at which a chemical substance reacts is proportional to its _____________________?

The preferred reacting system for oxidation of o-xylene to phthalic anhydride is _____________________?

The performance of a cascade of CSTR’s can be improved by adding__________________?

The order of the chemical reaction as shown in the bellow figure, whose rate equation is given as -rA = KCA_________________?

The order of a chemical reaction is__________________?

The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the_________________?

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

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

The minimum energy required to allow a chemical reaction to proceed is termed as the ‘threshold energy ‘. Chemical reactions with low activation energy are ________________?

The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of _______________ order?

The irreversible reaction, X → Y, is the special case of the reversible reaction, X ⇌ Y, in which the _____________________?

The irreversible reaction is a special case of reversible reaction, if the________________?

The increase in the rate of reaction with temperature is due to__________________?

The importance of diffusion in a catalyst are increased by ____________________?