8247 + Mcqs in Chemical Engineering Page 96 McqOptions

4751.	Bulk diffusion in catalyst pore __________ with increase in pressure.
A.	increases
B.	decreases
C.	remains unchanged
D.	increases exponentially
Answer» C. remains unchanged

Discussion

4752.	The following half life data are available for the irreversible liquid phase reaction A products.The overall order of reaction is
A.	0.5
B.	1
C.	1.5
D.	2
Answer» D. 2

Discussion

4753.	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

4754.	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

4755.	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)
A.	increases
B.	decreases
C.	remains same
D.	increases linearly
Answer» B. decreases

Discussion

4756.	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

Discussion

4757.	Which of the following factors control the deactivation of a porous catalyst pellet ?
A.	Decay reactions.
B.	Pore diffusion.
C.	Form of surface attack by poison.
D.	All (a), (b) and (c).
Answer» E.

Discussion

4758.	A liquid phase reaction is to be carried out under isothermal conditions. The reaction rate as a function of conversion has been determined experimentally and is shown in the figure given below. What choice of reactor or combination of reactors will require the minimum overall reactor volume, if a conversion of 0.9 is desired ?
A.	CSTR followed by a PFR
B.	PFR followed by a CSTR
C.	CSTR followed by a PFR followed by a CSTR.
D.	PFR followed by a CSTR followed by a PFR.
Answer» E.

Discussion

4759.	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

4760.	The experimentally determined overall order of the reaction, A + B C + D, 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

4761.	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

4762.	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

Discussion

4763.	The energy balance equation over a tubular reactor under transient conditions is
A.	an ordinary non-linear differential equation.
B.	an algebric differential equation.
C.	a linear partial differential equation.
D.	a non-linear partial differential equation.
Answer» D. a non-linear partial differential equation.

Discussion

4764.	In Langmuir treatment of adsorption,
A.	whole surface of the catalyst does not have the same activity for adsorption and there is attraction between the adsorbed molecule.
B.	whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site.
C.	all the adsorption does not take place by the same mechanism.
D.	extent of adsorption is more than one complete monomolecular layer on the surface.
Answer» C. all the adsorption does not take place by the same mechanism.

Discussion

4765.	Organic catalysts differ from the inorganic catalyst in the sense that the former is
A.	active at cryogenic temperatures only.
B.	prohibitively costly.
C.	proteinous in nature.
D.	active at very high temperature only.
Answer» D. active at very high temperature only.

Discussion

4766.	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

4767.	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

4768.	Which of the following is not a unit of reaction rate ?
A.	Moles for med/(surface of catalyst) (time)
B.	Moles formed/volume of reactor) (time)
C.	Mole formed/volume of catalyst) (time)
D.	None of these
Answer» E.

Discussion

4769.	Brunaur, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume & the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation ?
A.	Langmuir's assumption applies to every adsorbed layer.
B.	There is no dynamic equilibrium between successive layer.
C.	The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer (except the first one) is involved in each of the evaporation process.
D.	none of these.
Answer» C. The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer (except the first one) is involved in each of the evaporation process.

Discussion

4770.	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

4771.	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

4772.	The use of space time is preferred over the mean residence time in the design of a/an
A.	batch reactor
B.	ideal tubular-flow reactor
C.	slurry reactor
D.	CSTR
Answer» C. slurry reactor

Discussion

4773.	Autocatalytic reactions are best carried out in a
A.	CSTR
B.	CSTR in series
C.	plug flow reactor
D.	recycle reactor
Answer» E.

Discussion

4774.	The gas phase reaction 2A B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is
A.	2/3
B.	5/8
C.	1/3
D.	3/8
Answer» C. 1/3

Discussion

4775.	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

4776.	Mean residence time is equal to the space time, when
A.	the feed rate is measured at temperature and pressure in the reactor.
B.	the temperature, pressure and the density of reaction mixture remains constant throughout the reactor.
C.	there is no change in number of moles in gaseous reaction.
D.	all (a), (b) and (c).
Answer» E.

Discussion

4777.	The value of 'n' for a chemical reaction A B, whose reaction rate is CAn, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled.
A.	0
B.	1
C.	2
D.	3
Answer» E.

Discussion

4778.	Non-catalytic fluid-solid reactions are represented by __________ model.
A.	continuous reaction
B.	unreacted core
C.	both (a) and (b)
D.	neither (a) and (b)
Answer» D. neither (a) and (b)

Discussion

4779.	A pulse tracer is introduced in an ideal CSTR (with a mean residence time ) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be
A.	2
B.	0.5
C.	/0.693
D.	0.693
Answer» B. 0.5

Discussion

4780.	In a first order reaction, the time required to reduce the concentration of reactant from 1 mole/litre to 0.5 mole/litre will be __________ that required to reduce it from 10 moles/litre to 5 moles/litre in the same volume.
A.	more than
B.	less than
C.	same as
D.	data insufficient; can't be predicted.
Answer» D. data insufficient; can't be predicted.

Discussion

4781.	Photo-chemical reactions occur in presence of
A.	sunlight.
B.	darkness,
C.	solid catalysts.
D.	monochromatic radiation only.
Answer» B. darkness,

Discussion

4782.	Fractional conversion __________ for an exothermic reversible chemical reaction, when the temperature is maximum.
A.	increases
B.	remains unchanged
C.	decreases
D.	unpredictable from the data
Answer» D. unpredictable from the data

Discussion

4783.	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

4784.	In a CSTR __________ varies with time.
A.	reaction rate
B.	concentration
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» E.

Discussion

4785.	The following gas phase reactions are carried out isothermally in a CSTR.A 2R ; r1 = k1pA ;k1 = 20mole/(sec.m3 bar)A 3S ; r2 = k2 pA ;k2 = 40mole/(sec.m3 .bar)What is the maximum possible value of FR(mole/sec.) ?
A.	1/3
B.	1/2
C.	2/3
D.	2
Answer» D. 2

Discussion

4786.	As the chemical reaction proceeds, the rate of reaction
A.	increases.
B.	decreases.
C.	remains same.
D.	may increase or decrease depending on the type of reaction.
Answer» C. remains same.

Discussion

4787.	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.	1/2
B.	1/3
C.	1/4
D.	1/5
Answer» C. 1/4

Discussion

4788.	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

4789.	Fluidised bed reactor is characterised by
A.	uniformity of temperature.
B.	comparatively smaller equipment.
C.	very small pressure drop.
D.	absence of continuous catalyst regeneration facility.
Answer» B. comparatively smaller equipment.

Discussion

4790.	Space time equals the mean residence time
A.	when the density of the reaction mixture is constant.
B.	for large diameter tubular reactor.
C.	for narrow diameter tubular reactor.
D.	for CSTR.
Answer» B. for large diameter tubular reactor.

Discussion

4791.	A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be __________ minutes.
A.	4
B.	8
C.	12
D.	16
Answer» E.

Discussion

4792.	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

4793.	Backmixing is most predominant in
A.	a well stirred batch reactor.
B.	a plug-flow reactor.
C.	a single CSTR.
D.	CSTR's connected in series.
Answer» D. CSTR's connected in series.

Discussion

4794.	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

Discussion

4795.	Consider a reversible exothermic reaction in a plug flow reactor. The maximum and minimum permissible temperatures are Tmax and Tmin respectively. Which of the following temperature (T) profiles will require the shortest residence time to achieve the desired conversion.
A.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/478-497-1.png">
B.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/478-497-2.png">
C.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/478-497-3.png">
D.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/478-497-4.png">
Answer» C. <img src="/_files/images/chemical-engineering/chemical-reaction-engineering/478-497-3.png">

Discussion

4796.	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

4797.	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

4798.	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

Discussion

4799.	Carbon particles accummulated on the catalyst used in the gas oil cracking lies in the category of __________ poison.
A.	deposited
B.	chemisorbed
C.	selectivity
D.	stability
Answer» B. chemisorbed

Discussion

4800.	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

Explore topic-wise MCQs in Engineering.

Bulk diffusion in catalyst pore __________ with increase in pressure.

The following half life data are available for the irreversible liquid phase reaction A products.The overall order of reaction is

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

The unit of frequency factor in Arhenious equation is

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)

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

Which of the following factors control the deactivation of a porous catalyst pellet ?

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 experimentally determined overall order of the reaction, A + B C + D, is two. Then the

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

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.

The energy balance equation over a tubular reactor under transient conditions is

In Langmuir treatment of adsorption,

Organic catalysts differ from the inorganic catalyst in the sense that the former is

The equilibrium constant K of a chemical reaction depends on

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

Which of the following is not a unit of reaction rate ?

Brunaur, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume &amp; the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation ?

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

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

The use of space time is preferred over the mean residence time in the design of a/an

Autocatalytic reactions are best carried out in a

The gas phase reaction 2A B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is

The rate constant of a reaction is a function of the

Mean residence time is equal to the space time, when

The value of 'n' for a chemical reaction A B, whose reaction rate is CAn, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled.

Non-catalytic fluid-solid reactions are represented by __________ model.

A pulse tracer is introduced in an ideal CSTR (with a mean residence time ) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be

In a first order reaction, the time required to reduce the concentration of reactant from 1 mole/litre to 0.5 mole/litre will be __________ that required to reduce it from 10 moles/litre to 5 moles/litre in the same volume.

Photo-chemical reactions occur in presence of

Fractional conversion __________ for an exothermic reversible chemical reaction, when the temperature is maximum.

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

In a CSTR __________ varies with time.

The following gas phase reactions are carried out isothermally in a CSTR.A 2R ; r1 = k1pA ;k1 = 20mole/(sec.m3 bar)A 3S ; r2 = k2 pA ;k2 = 40mole/(sec.m3 .bar)What is the maximum possible value of FR(mole/sec.) ?

As the chemical reaction proceeds, the rate of reaction

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

The rate of reaction does not decrease appreciably as the reaction proceeds in case of __________ reactions.

Fluidised bed reactor is characterised by

Space time equals the mean residence time

A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be __________ minutes.

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

Backmixing is most predominant in

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)

Consider a reversible exothermic reaction in a plug flow reactor. The maximum and minimum permissible temperatures are Tmax and Tmin respectively. Which of the following temperature (T) profiles will require the shortest residence time to achieve the desired conversion.

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

The rate of reaction of a/an __________ reaction is not affected by temperature rise.

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

Carbon particles accummulated on the catalyst used in the gas oil cracking lies in the category of __________ poison.

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 &amp; B were doubled and quandrupled when the concentrations of both B &amp; C were doubled ?

Brunaur, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume & the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation ?

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 ?