1443 + Mcqs in Chemical Reaction Engineering Page 20 McqOptions

951.	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
A.	1
B.	2
C.	3
D.	0
Answer» D. 0

Discussion

952.	Which of the following is an autocatalytic reaction ?
A.	Photochemical reactions
B.	Microbial fermentation reaction
C.	Enzyme fermentation reaction
D.	Ammonia synthesis reaction
Answer» C. Enzyme fermentation reaction

Discussion

953.	A non-catalytic chemical reaction of the type is called a __________ reaction.
A.	parallel
B.	series
C.	series-parallel
D.	none of these
Answer» D. none of these

Discussion

954.	Which of the following is a controlling factor in very fast heterogeneous reaction ?
A.	Heat and mass transfer effects
B.	Pressure
C.	Temperature
D.	Composition of reactant
Answer» B. Pressure

Discussion

955.	Space time in flow reactor is
A.	usually equal to the residence time.
B.	the reciprocal of the space velocity.
C.	a measure of its capacity.
D.	both (a) and (b).
Answer» E.

Discussion

956.	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

Discussion

957.	With increase in temperature, the equilibrium conversion of a reversible exothermic reaction
A.	decreases
B.	increases
C.	remains unaffected
D.	decreases linearily with temperature
Answer» B. increases

Discussion

958.	Second order consecutive irreversible reactions were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2)?
A.	43556
B.	43497
C.	2
D.	4
Answer» B. 43497

Discussion

959.	If Thiele modulus is __________ , then the pore diffusion resistance in a catalyst may be considered as negligible.
A.	0
B.	‚àû
C.	< 0.5
D.	> 0.5
Answer» D. > 0.5

Discussion

960.	At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500¬∞K and 400¬∞K is 2, if Arrhenious law is used. What will be this ratio, if transition state theory is used with the same value of E/R?$
A.	1.6
B.	2
C.	2.24
D.	2.5
Answer» E.

Discussion

961.	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» D. 0

Discussion

962.	With the same reaction time, initial concentration and feed rate, the reaction 2A B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be
A.	higher in P.F. reactor
B.	higher in CSTR
C.	same in both the reactors
D.	data insufficient; can't be predicted
Answer» B. higher in CSTR

Discussion

963.	A first order irreversible reaction, A B 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

964.	During manufacture of H2SO4, the oxidation of SO2 to SO3 by oxygen is an en-dothermic reaction. The yield of SO3 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

965.	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

966.	With increase in initial concentration, the fractional conversion of a first order reaction in a given time
A.	increases
B.	decreases
C.	remains constant
D.	unpredictable
Answer» D. unpredictable

Discussion

967.	The effect of increasing pressure on the gaseous equilibrium of the reaction 2X+3Y 3X+2Y indicates that
A.	pressure has no effect.
B.	backward reaction is favoured.
C.	forward reaction is favoured.
D.	none of these.
Answer» B. backward reaction is favoured.

Discussion

968.	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

969.	Reaction rate equation for the reaction, . If S 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

970.	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

971.	Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N2 + 3H2 2NH3.
A.	increases
B.	decreases
C.	remains unchanged
D.	unpredictable from the data
Answer» B. decreases

Discussion

972.	The unit of frequency factor in Arhenious equation is
A.	same as that of rate constant.
B.	same as that of activation energy.
C.	dimensionless.
D.	none of these.
Answer» B. same as that of activation energy.

Discussion

973.	For reaction, P + 2 3R, molar rate of consumption of P is
A.	double of that of Q.
B.	same as that of Q.
C.	half of that of Q.
D.	2/3rd of that of Q.
Answer» D. 2/3rd of that of Q.

Discussion

974.	Rate of a gaseous phase reaction is given by, . The unit of rate constant is
A.	(atm)-1
B.	(hr)-1
C.	(atm)-1.(hr)-1
D.	atm.(hr)-1
Answer» D. atm.(hr)-1

Discussion

975.	The 'E' curve for a non-ideal reactor defines the fraction of fluid having age between t and t + dt
A.	at the inlet
B.	at the outlet
C.	in the reactor
D.	averaged over the inlet and outlet
Answer» C. in the reactor

Discussion

976.	Design of heterogeous catalytic reactor involves consideration of __________ steps.
A.	only chemical
B.	only physical
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

Discussion

977.	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.

Discussion

978.	With decrease in temperature, the equilibrium conversion of a reversible endother-mic reaction
A.	decreases
B.	increases
C.	remains unaffected
D.	increases linearly with temperature
Answer» B. increases

Discussion

979.	An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is
A.	maximum at the inlet of the reactor.
B.	maximum at the exit of the reactor.
C.	maximum at the centre of the reactor.
D.	constant throughout the reactor.
Answer» B. maximum at the exit of the reactor.

Discussion

980.	Which of the following fixes the volume of a batch reactor for a particular conversion and production rate ?
A.	Operating conditions (e.g. pressure and temperature)
B.	Rate constant
C.	Density of mixture
D.	None of these
Answer» D. None of these

Discussion

981.	For every 10¬∞C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70¬∞C, the rate of reaction increases __________ times.$
A.	8
B.	12
C.	16
D.	32
Answer» D. 32

Discussion

982.	The reaction A B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3 is 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

983.	B.E.T. method of finding out surface area of a catalyst, uses the extension of __________ isotherm.
A.	Langmuir
B.	Freundlich
C.	Tempkin
D.	none of these
Answer» B. Freundlich

Discussion

984.	__________ is the response curve for a step input signal from a reactor.
A.	S-curve
B.	C-curve
C.	I-curve
D.	none of these
Answer» C. I-curve

Discussion

985.	The exit age distribution curve E(t) for an ideal CSTR with the average residence time, œÑ, is given by$
A.	e-t/œÑ
B.
Answer» C.

Discussion

986.	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$
A.	5¬∞C
B.	10¬∞C
C.	20¬∞C
D.	100¬∞C
Answer» C. 20¬∞C

Discussion

987.	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.

Discussion

988.	Pure A in gas phase enters a reactor 50% of this A is converted to B through the reaction, A 3B. Mole fraction of A in the exit stream is
A.	43497
B.	43525
C.	43556
D.	43586
Answer» C. 43556

Discussion

989.	In the reversible reaction of the type, A + B AB, in general
A.	both forward and backward reactions will be exothermic.
B.	neither of the reactions will be en-dothermic.
C.	the combination reaction will be exothermic, while the dissociation reaction will be endothermic.
D.	the combination reaction will be endothermic, while the dissociation reaction will be exothermic.
Answer» D. the combination reaction will be endothermic, while the dissociation reaction will be exothermic.

Discussion

990.	Rate of a chemical reaction is independent of the concentration of the reactants for a __________ reaction.
A.	zero order
B.	third order
C.	consecutive
D.	none of these
Answer» B. third order

Discussion

991.	Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as
A.	DE = DM + DK
B.
C.	DE = DM . DE
D.	DE = DN/DE
Answer» C. DE = DM . DE

Discussion

992.	The fractional volume change between no conversion and complete conversion, for the isothermal gas phase reaction, 2A R, is
A.	0.5
B.	-0.5
C.	1
D.	1.5
Answer» C. 1

Discussion

993.	The effectiveness factor for large value of Thiele modulus (LK/D1) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm2/second)
A.	L(K/D1)
B.	1/(LK/D1)
C.	1
D.	‚àû
Answer» C. 1

Discussion

994.	What is the order of chemical reaction , if itis found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quandrupled when the concentrations of both B & C were doubled ?
A.	1
B.	2
C.	3
D.	4
Answer» C. 3

Discussion

995.	The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst.
A.	increases
B.	decreases
C.	remains unaffected
D.	unpredictable from the data
Answer» D. unpredictable from the data

Discussion

996.	If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is
A.	0
B.	1
C.	2
D.	3
Answer» D. 3

Discussion

997.	The single parameter model proposed for describing non-ideal flow is the __________ model.
A.	tank in series
B.	dispersion
C.	both (a) & (b)
D.	neither (a) nor (b).
Answer» D. neither (a) nor (b).

Discussion

998.	In the hydrodealkylation of toluene to benzene, the following reactions occur:C7H8 + H2 C6H6 + CH42C6H6 C12H10 + H2Toluene 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

999.	For a __________ order chemical reaction, , the fractional conversion of reactant 'A' is proportional to time.
A.	zero
B.	first
C.	second
D.	third
Answer» B. first

Discussion

1000.	For the reversible reaction A 2B, if the equilibrium constant K is 0.05 mole/litre; starting from initially 2 moles of A and zero moles of B, how many moles will be formed at equilibrium ?
A.	0.253
B.	0.338
C.	0.152
D.	0.637
Answer» C. 0.152

Discussion

Explore topic-wise MCQs in Chemical Engineering.

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

Which of the following is an autocatalytic reaction ?

A non-catalytic chemical reaction of the type is called a __________ reaction.

Which of the following is a controlling factor in very fast heterogeneous reaction ?

Space time in flow reactor is

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

With increase in temperature, the equilibrium conversion of a reversible exothermic reaction

If Thiele modulus is __________ , then the pore diffusion resistance in a catalyst may be considered as negligible.

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500¬∞K and 400¬∞K is 2, if Arrhenious law is used. What will be this ratio, if transition state theory is used with the same value of E/R?$

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

With the same reaction time, initial concentration and feed rate, the reaction 2A B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be

A first order irreversible reaction, A B 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.

During manufacture of H2SO4, the oxidation of SO2 to SO3 by oxygen is an en-dothermic reaction. The yield of SO3 will be maximised, if the

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

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

The effect of increasing pressure on the gaseous equilibrium of the reaction 2X+3Y 3X+2Y indicates that

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

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

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

Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N2 + 3H2 2NH3.

The unit of frequency factor in Arhenious equation is

For reaction, P + 2 3R, molar rate of consumption of P is

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

The 'E' curve for a non-ideal reactor defines the fraction of fluid having age between t and t + dt

Design of heterogeous catalytic reactor involves consideration of __________ steps.

The equilibrium constant K of a chemical reaction depends on

With decrease in temperature, the equilibrium conversion of a reversible endother-mic reaction

An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is

Which of the following fixes the volume of a batch reactor for a particular conversion and production rate ?

For every 10¬∞C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70¬∞C, the rate of reaction increases __________ times.$

B.E.T. method of finding out surface area of a catalyst, uses the extension of __________ isotherm.

__________ is the response curve for a step input signal from a reactor.

The exit age distribution curve E(t) for an ideal CSTR with the average residence time, œÑ, is given by$

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$

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

Pure A in gas phase enters a reactor 50% of this A is converted to B through the reaction, A 3B. Mole fraction of A in the exit stream is

In the reversible reaction of the type, A + B AB, in general

Rate of a chemical reaction is independent of the concentration of the reactants for a __________ reaction.

Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as

The fractional volume change between no conversion and complete conversion, for the isothermal gas phase reaction, 2A R, is

The effectiveness factor for large value of Thiele modulus (LK/D1) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm2/second)

What is the order of chemical reaction , if itis found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quandrupled when the concentrations of both B & C were doubled ?

The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst.

If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is

The single parameter model proposed for describing non-ideal flow is the __________ model.

For a __________ order chemical reaction, , the fractional conversion of reactant 'A' is proportional to time.

For the reversible reaction A 2B, if the equilibrium constant K is 0.05 mole/litre; starting from initially 2 moles of A and zero moles of B, how many moles will be formed at equilibrium ?