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

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

Surface reaction between absorbed A and absorbed B

Surface reaction between A in the gas phase and absorbed B

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

Data insufficient, can't be predicted

A space velocity of 5 hr⁻¹ means that

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

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

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

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

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

The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reaction with low activation energy are%!

Insensitive to temperature changes

A chemical reaction, A ‚Äö√ú√≠ 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%!

Data insufficient, can't be predicted

The rate expression for a heterogenous 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 ≈í√ÆHR and ≈í√ÆHA are the activation energies of adsorption of R and A)%!

E + ≈í√ÆHA - ≈í√ÆHR

Chemical reaction rate of a component depends upon the%!

Composition of the component only

Rate determining step in a reaction consisting of a number of steps in series is the __________ step.%!

Data insufficient; can't be predicted

Considering the endotheomic dissociation of CaCO‚Äö√á√â in a closed vessel (CaCO‚Äö√á√â ‚Äö√°√£ CaO + CO‚Äö√á√á), the pressure of CO‚Äö√á√á increases, if%!

An inert gas is pumped keeping the temperature constant

Transition state theory gives the rate constant as%!

K ≈í¬± ‚Äö√ √∂T . e-E/RT

For a tubular reactor with space time '≈ì√ë' and residence time '≈í‚àè', the following statement holds good.%!

≈ì√ë = ≈í‚àè , for a non-isothermal reactor

≈ì√ë and ≈í‚àè are always equal

≈ì√ë = ≈í‚àè , when the fluid density changes in the reactor

≈ì√ë = ≈í‚àè , for an isothermic tubular reactor in which the density of the process fluid is constant

≈ì√ë = ≈í‚àè , for a non-isothermal reactor

The rate constant of a reaction depends on the%!

Initial concentration of reactants

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

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant%!

Increases /decreases with pressure depending on the stoichiometric co-efficients of the reaction

"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 ‚Äö√ú√≠ 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."%!

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

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

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

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

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

1443 + Mcqs in Chemical Reaction Engineering Page 8 McqOptions

351.	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» E.

352.	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
A.	0.33
B.	0.5
C.	1
D.	Data insufficient, can't be predicted
Answer» D. Data insufficient, can't be predicted

353.	Consider the 'n' th order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction (t1/2) and the initial reactant concentration (CA0) gives a straight line plot?
A.	CA0 Vs t1/2
B.	Ln CA0 Vs t1/2
C.	CA0 Vs ln t1/2
D.	Ln CA0 Vs ln t1/2
Answer» D. Ln CA0 Vs ln t1/2

354.	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)
A.	Decreases
B.	Increases
C.	Remains unaltered
D.	Changes unpredictably
Answer» B. Increases

355.	A space velocity of 5 hr⁻¹ means that
A.	Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour
B.	After every 5 hours, reactor is being filled with the feed
C.	Cent per cent conversion can be achieved in at least 5 hours
D.	A fixed conversion of a given batch of feed takes 5 hours
Answer» B. After every 5 hours, reactor is being filled with the feed

356.	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

357.	In the converter of the contact process for the manufacture of H₂SO₄ the equilibrium conversion of SO₂ __________ (i) __________ with increase in temperature and __________ (ii) __________ with increase in the mole ratio of SO₂ to air.
A.	(i) increases (ii) decreases
B.	(i) decreases (ii) increases
C.	(i) increases (ii) increases
D.	(i) decreases (ii) decreases
Answer» C. (i) increases (ii) increases

358.	For a mixed flow reactor operating at steady state, the rate of reaction is given by
A.	FA0/V - dCsub>A/dt
B.	FA0/V + dCsub>A/dt
C.	FA0/V . Xsub>A
D.	- dCsub>A/dt
Answer» D. - dCsub>A/dt

359.	In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation.~!
A.	Adiabatic
B.	Isothermal
C.	Non-adiabatic
D.	None of these
Answer» D. None of these

360.	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

361.	The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reaction with low activation energy are%!
A.	Always irreversible
B.	Insensitive to temperature changes
C.	Mostly irreversible
D.	Highly temperature sensitive
Answer» C. Mostly irreversible

363.	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.	‚Äö√ √∂m
C.	m¬¨‚â§
Answer» C. m¬¨‚â§

366.	A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to%!
A.	Lose a proton
B.	Gain a proton
C.	Lose an electron
D.	None of these
Answer» B. Gain a proton

368.	Helium-mercury method can be used to determine the __________ of the catalyst particle.%!
A.	Pore volume
B.	Solid density
C.	Porosity
D.	All of the above
Answer» E.

369.	B.E.T. method can be used to determine the __________ of a porous catalyst.%!
A.	Solid density
B.	Pore volume
C.	Surface area
D.	All of the above
Answer» D. All of the above

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

364.	Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N‚Äö√á√á + 3H‚Äö√á√á ‚Äö√°√£ 2NH‚Äö√á√â.%!
A.	Increases
B.	Decreases
C.	Remains unchanged
D.	Unpredictable from the data
Answer» B. Decreases

365.	When a catalyst increases the rate of chemical reaction, the rate constant%!
A.	Decreases
B.	Increases
C.	Remains constant
D.	Becomes infinite
Answer» C. Remains constant

367.	A chemical reaction, A ‚Äö√ú√≠ 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%!
A.	0.33
B.	0.5
C.	1
D.	Data insufficient, can't be predicted
Answer» D. Data insufficient, can't be predicted

370.	What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on?%!
A.	Litre/mole.second
B.	Moles/litre.second
C.	Litre/mole
D.	Litre/second
Answer» B. Moles/litre.second

371.	The equilibrium constant K of a chemical reaction depends on%!
A.	Temperature only
B.	Pressure only
C.	Temperature and pressure
D.	Ratio of reactants
Answer» B. Pressure only

372.	A multiple reaction may be classified as a __________ reaction.%!
A.	Consecutive or side
B.	Parallel or side
C.	Mixed
D.	All of the above
Answer» E.

373.	The rate expression for a heterogenous 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 ≈í√ÆHR and ≈í√ÆHA are the activation energies of adsorption of R and A)%!
A.	E
B.	E + ≈í√ÆHA
C.	E + ≈í√ÆHA - ≈í√ÆHR
D.	≈í√ÆHA + ≈í√ÆHR
Answer» D. ≈í√ÆHA + ≈í√ÆHR

374.	Chemical reaction rate of a component depends upon the%!
A.	Composition of the component only
B.	Temperature of the system
C.	Pressure of the system
D.	All of the above
Answer» E.

375.	Rate determining step in a reaction consisting of a number of steps in series is the __________ step.%!
A.	Fastest
B.	Slowest
C.	Intermediate
D.	Data insufficient; can't be predicted
Answer» C. Intermediate

Explore topic-wise MCQs in Chemical Engineering.

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 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

Consider the 'n' th order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction (t1/2) and the initial reactant concentration (CA0) gives a straight line plot?

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)

A space velocity of 5 hr⁻¹ means that

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

In the converter of the contact process for the manufacture of H₂SO₄ the equilibrium conversion of SO₂ __________ (i) __________ with increase in temperature and __________ (ii) __________ with increase in the mole ratio of SO₂ to air.

For a mixed flow reactor operating at steady state, the rate of reaction is given by

In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation.~!

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

The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reaction with low activation energy are%!

Reactions with high activation energy are%!

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%!

Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N‚Äö√á√á + 3H‚Äö√á√á ‚Äö√°√£ 2NH‚Äö√á√â.%!

When a catalyst increases the rate of chemical reaction, the rate constant%!

A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to%!

A chemical reaction, A ‚Äö√ú√≠ 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%!

Helium-mercury method can be used to determine the __________ of the catalyst particle.%!

B.E.T. method can be used to determine the __________ of a porous catalyst.%!

What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on?%!

The equilibrium constant K of a chemical reaction depends on%!

A multiple reaction may be classified as a __________ reaction.%!

Chemical reaction rate of a component depends upon the%!

Rate determining step in a reaction consisting of a number of steps in series is the __________ step.%!

When a catalyst increases the rate of forward reaction, the value of rate constant%!

The vessel dispersion number (D/≈í¬∫L) for plug flow is%!

__________ explains the mechanism of catalysis.%!

Vegetable oils are hydrogenated in a __________ reactor.%!

Considering the endotheomic dissociation of CaCO‚Äö√á√â in a closed vessel (CaCO‚Äö√á√â ‚Äö√°√£ CaO + CO‚Äö√á√á), the pressure of CO‚Äö√á√á increases, if%!

In a CSTR __________ varies with time.%!

Transition state theory gives the rate constant as%!

Radioactive decay follows __________ order kinetics.%!

For every 10¬¨‚àûC rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70¬¨‚àûC, the rate of reaction increases __________ times.%!

For a tubular reactor with space time '≈ì√ë' and residence time '≈í‚àè', the following statement holds good.%!

The enzyme which can catalyse the conversion of glucose to ethyl alcohol is%!

From Arhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is%!

Higher free energy of activation of a chemical reaction (at a given temperature) implies%!

__________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction.%!

The sequence in which three CSTR's of volumes 5, 10 and 15 m¬¨‚â• will be connected in series to obtain the maximum production in a second order irreversible reaction is%!

The rate constant of a reaction depends on the%!

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

For a heterogeneous catalytic reaction%!

For identical flow rate and feed composition, X plug flow reactors (PER) in series with a total volume V gives the same conversion as single%!

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant%!

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

The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of __________ order.%!

Fluid flow in a real packed bed can be approximated as __________ model.%!

When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is%!

In the converter of the contact process for the manufacture of H₂SO₄ the equilibrium conversion of SO₂ (i) with increase in temperature and (ii) with increase in the mole ratio of SO₂ to air.

376.	When a catalyst increases the rate of forward reaction, the value of rate constant%!
A.	Increases
B.	Decreases
C.	Remain same
D.	Becomes infinite
Answer» B. Decreases

377.	The vessel dispersion number (D/≈í¬∫L) for plug flow is%!
A.	0
B.	500
C.	750
D.	‚Äö√ √ª
Answer» B. 500

378.	__________ explains the mechanism of catalysis.%!
A.	Activated complex theory
B.	Collision theory
C.	Thermodynamics
D.	None of these
Answer» B. Collision theory

379.	Vegetable oils are hydrogenated in a __________ reactor.%!
A.	Slurry
B.	Plug flow
C.	Homogeneous catalytic
D.	None of these
Answer» B. Plug flow

380.	Considering the endotheomic dissociation of CaCO‚Äö√á√â in a closed vessel (CaCO‚Äö√á√â ‚Äö√°√£ CaO + CO‚Äö√á√á), the pressure of CO‚Äö√á√á 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

381.	In a CSTR __________ varies with time.%!
A.	Reaction rate
B.	Concentration
C.	Both A & B
D.	Neither A nor B
Answer» E.

382.	Transition state theory gives the rate constant as%!
A.	K ≈í¬± e-E/RT
B.	K ≈í¬± eE/RT
C.	K ≈í¬± T . e-E/RT
D.	K ≈í¬± ‚Äö√ √∂T . e-E/RT
Answer» D. K ≈í¬± ‚Äö√ √∂T . e-E/RT

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

384.	For every 10¬¨‚àûC rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70¬¨‚àûC, the rate of reaction increases __________ times.%!
A.	8
B.	12
C.	16
D.	32
Answer» D. 32

385.	For a tubular reactor with space time '≈ì√ë' and residence time '≈í‚àè', the following statement holds good.%!
A.	≈ì√ë and ≈í‚àè are always equal
B.	≈ì√ë = ≈í‚àè , when the fluid density changes in the reactor
C.	≈ì√ë = ≈í‚àè , for an isothermic tubular reactor in which the density of the process fluid is constant
D.	≈ì√ë = ≈í‚àè , for a non-isothermal reactor
Answer» D. ≈ì√ë = ≈í‚àè , for a non-isothermal reactor