In case of a P.F.R., there

Should not be any mixing along the flow path

Initiates a chemical reaction and is a catalyst by itself

Alters the position of equilibrium in a reversible reaction

Increases the number of active centres by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals

The concentration of A in a first order reaction, A → B, decreases

Very abruptly towards the end of the reaction

Differential method for analysing the kinetic data is used

For testing complicated mechanisms

When rate expressions are very simple

The catalyst in a first order chemical reaction changes the

Heat of formation of the product

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

For a tubular reactor with space time 'η' and residence time 'ζ', the following statement holds good.

η = θ, for a non-isothermal reactor

η = θ, when the fluid density changes in the reactor

η = θ, for an isothermic tubular reactor in which the density of the process fluid is constant

η = θ, for a non-isothermal reactor

A rise in temperature

Normally tends to increase the reaction rate

Does not affect a catalysed reaction

Does not affect photo-chemical reaction rates

The extent of a reaction is

Different for reactants and products

Depends on the stoichiometric co-efficient

BET apparatus is used to determine the

Specific surface of a porous catalyst

In the fluid catalytic cracker (FCC), the cracking reaction is __________ (i) and the regeneration is__________ (ii) __________.

(i) exothermic (ii) endothermic

(i) endothermic (ii) endothermic

(i) endothermic (ii) exothermic

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, cant be predicted

The rate constant of a reaction is a function of the

Initial concentration of the reactants

A plug-flow reactor is characterised by

Constant composition and temperature of reaction mixture

1443 + Mcqs in Chemical Reaction Engineering in Chemical Engineering Page 27 McqOptions

1301.	In case of a P.F.R., there
A.	May be lateral mixing of fluid
B.	Should not be any mixing along the flow path
C.	Both (A) and (B)
D.	Neither (A) nor (B)
Answer» D. Neither (A) nor (B)

Discussion

1302.	Promoter
A.	Initiates a chemical reaction and is a catalyst by itself
B.	Alters the position of equilibrium in a reversible reaction
C.	Increases the number of active centres by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals
D.	All (A), (B) and (C)
Answer» D. All (A), (B) and (C)

Discussion

1303.	For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by
A.	A Dirac delta function
B.	A step function
C.	A ramp function
D.	None of the above
Answer» E.

Discussion

1304.	In the hydrodealkylation of toluene to benzene, the following reactions occur: C7H8 + H2 → C6H6 + CH4 2C6H6 ⇌ C12H10 + H2 www.objectivebooks.com Toluene 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

1305.	Vegetable oils are hydrogenated in a __________ reactor.
A.	Slurry
B.	Plug flow
C.	Homogeneous catalytic
D.	None of these
Answer» B. Plug flow

Discussion

1306.	A typical example of an exothermic reversible reaction conducted at high pressure in industry is
A.	Dehydration of ethanol
B.	Methanol synthesis
C.	Reformation of methane
D.	Polymerisation of ethylene
Answer» B. Methanol synthesis

Discussion

1307.	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

1308.	Reaction rate of a first order reaction, which is half completed in 23 minutes will be
A.	0.03 sec-1
B.	0.03 min-1
C.	0.03 hr-1
D.	0.05 min-1
Answer» C. 0.03 hr-1

Discussion

1309.	Half life period of a chemical reaction is proportional to CA0 -1 , if the reaction is of __________ order.
A.	First
B.	Zero
C.	Second
D.	Third
Answer» D. Third

Discussion

1310.	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

1311.	Chemical kinetics can predict the __________ of a chemical reaction.
A.	Rate
B.	Feasibility
C.	Both (A) & (B)
D.	Neither (A) nor (B)
Answer» B. Feasibility

Discussion

1312.	'n' number of plug flow reactors (P.F.R) in series with a total volume 'V' gives the same conversion as one P.F.R. of volume
A.	V/n
B.	V
C.	V.n
D.	1/V
Answer» C. V.n

Discussion

1313.	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

Discussion

1314.	The concentration of A in a first order reaction, A → B, decreases
A.	Linearly with time
B.	Exponentially with time
C.	Very abruptly towards the end of the reaction
D.	Logarithmically with time
Answer» C. Very abruptly towards the end of the reaction

Discussion

1315.	The reactions with low activation energy are
A.	Always spontaneous
B.	Slow
C.	Fast
D.	Non-spontaneous
Answer» D. Non-spontaneous

Discussion

1316.	Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about __________ minutes.
A.	3
B.	4
C.	6
D.	10
Answer» C. 6

Discussion

1317.	Rate of an autocatalytic chemical reaction is a function of
A.	Temperature only
B.	Pressure only
C.	Composition only
D.	All (A), (B) and (C)
Answer» E.

Discussion

1318.	A first order reaction A → B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A 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

1319.	Oil is hydrogenated using nickel catalyst in a __________ reactor
A.	Batch
B.	Slurry
C.	Fluidised bed
D.	Fixed bed
Answer» C. Fluidised bed

Discussion

1320.	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

1321.	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

1322.	Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually __________ the concentration of catalyst, if it does not entail a chain mechanism.
A.	Proportional to
B.	Independent of
C.	Inversely proportional to
D.	Proportional to the square of
Answer» B. Independent of

Discussion

1323.	Which of the following is not endothermic in nature?
A.	Combustion of sulphur
B.	Gasification of carbon
C.	Thermal cracking of fuel oil
D.	Steam reforming of naphtha
Answer» B. Gasification of carbon

Discussion

1324.	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

1325.	Differential method for analysing the kinetic data is used
A.	For testing complicated mechanisms
B.	When the data are scattered
C.	When rate expressions are very simple
D.	None of these
Answer» B. When the data are scattered

Discussion

1326.	For a tubular flow reactor with uniform concentration and temperature, the independent variable is
A.	Time
B.	Length
C.	Diameter
D.	None of these
Answer» C. Diameter

Discussion

1327.	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
A.	CSTR of volume V
B.	PFR of volume V
C.	CSTR of volume V/X
D.	PFR of volume V/X
Answer» C. CSTR of volume V/X

Discussion

1328.	In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO2 to SO3 is accomplished by a __________ reaction.
A.	Non-catalytic homogeneous
B.	Non-catalytic heterogeneous
C.	Catalytic homogenous
D.	Catalytic heterogeneous
Answer» D. Catalytic heterogeneous

Discussion

1329.	The catalyst in a first order chemical reaction changes the
A.	Equilibrium constant
B.	Activation energy
C.	Heat of formation of the product
D.	Heat of reaction
Answer» C. Heat of formation of the product

Discussion

1330.	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

1331.	For a tubular reactor with space time 'η' and residence time 'ζ', the following statement holds good.
A.	η and θ are always equal
B.	η = θ, when the fluid density changes in the reactor
C.	η = θ, for an isothermic tubular reactor in which the density of the process fluid is constant
D.	η = θ, for a non-isothermal reactor
Answer» D. η = θ, for a non-isothermal reactor

Discussion

1332.	For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of:
A.	Ideal plug flow
B.	Bypass
C.	Dead zone
D.	Channelling
Answer» D. Channelling

Discussion

1333.	Kinetics of a solid catalysed reaction can best be studied in a __________ reactor.
A.	Batch
B.	Plug-flow
C.	Mixed
D.	None of these
Answer» D. None of these

Discussion

1334.	Half life period of decomposition of a liquid 'A' by irreversible first order reaction is 12 minutes. The time required for 75% conversion of 'A' is __________ minutes.
A.	18
B.	24
C.	6
D.	12
Answer» C. 6

Discussion

1335.	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

1336.	Arrhenius equation represents graphically the variation between the __________ and temperature.
A.	Rate of reaction
B.	Frequency factor
C.	Rate constant
D.	Activation energy
Answer» D. Activation energy

Discussion

1337.	A rise in temperature
A.	Normally tends to increase the reaction rate
B.	Does not affect a catalysed reaction
C.	Does not affect photo-chemical reaction rates
D.	All (A), (B) and (C)
Answer» E.

Discussion

1338.	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

1339.	BET apparatus is used to determine the
A.	Specific surface of a porous catalyst
B.	Pore size distribution
C.	Pore diameter
D.	Porosity of the catalyst bed
Answer» B. Pore size distribution

Discussion

1340.	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

1341.	Effectiveness factor of a catalyst pellet is a measure of the __________ resistance.
A.	Pore diffusion
B.	Gas film
C.	Chemical reaction
D.	None of these
Answer» B. Gas film

Discussion

1342.	Bulk diffusion in catalyst pore __________ with increase in pressure.
A.	Increases
B.	Decreases
C.	Remains unchanged
D.	Increases exponentially
Answer» C. Remains unchanged

Discussion

1343.	In the fluid catalytic cracker (FCC), the cracking reaction is __________ (i) and the regeneration is__________ (ii) __________.
A.	(i) exothermic (ii) endothermic
B.	(i) exothermic (ii) exothermic
C.	(i) endothermic (ii) endothermic
D.	(i) endothermic (ii) exothermic
Answer» E.

Discussion

1344.	Autocatalytic reactions are best carried out in a
A.	CSTR
B.	CSTR in series
C.	Plug flow reactor
D.	Recycle reactor
Answer» E.

Discussion

1345.	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, cant be predicted
Answer» D. Data insufficient, cant be predicted

Discussion

1346.	Cold shot cooling is only practical when the feed temperature is __________ than the reaction temperature.
A.	Higher
B.	Much higher
C.	Lower
D.	Much lower
Answer» E.

Discussion

1347.	The rate constant of a reaction is a function of the
A.	Time of reaction
B.	Time of reaction
C.	Extent of reaction
D.	Initial concentration of the reactants
Answer» C. Extent of reaction

Discussion

1348.	A plug-flow reactor is characterised by
A.	High capacity
B.	Presence of axial mixing
C.	Presence of lateral mixing
D.	Constant composition and temperature of reaction mixture
Answer» D. Constant composition and temperature of reaction mixture

Discussion

1349.	The vessel dispersion number (D/μL) for plug flow is
A.	0
B.	500
C.	750
D.	∞
Answer» B. 500

Discussion

1350.	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

Explore topic-wise MCQs in Chemical Engineering.

In case of a P.F.R., there

Promoter

For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by

Vegetable oils are hydrogenated in a __________ reactor.

A typical example of an exothermic reversible reaction conducted at high pressure in industry is

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

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

Half life period of a chemical reaction is proportional to CA0 -1 , if the reaction is of __________ order.

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

Chemical kinetics can predict the __________ of a chemical reaction.

'n' number of plug flow reactors (P.F.R) in series with a total volume 'V' gives the same conversion as one P.F.R. of volume

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

The concentration of A in a first order reaction, A → B, decreases

The reactions with low activation energy are

Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about __________ minutes.

Rate of an autocatalytic chemical reaction is a function of

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

Oil is hydrogenated using nickel catalyst in a __________ reactor

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

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

Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually __________ the concentration of catalyst, if it does not entail a chain mechanism.

Which of the following is not endothermic in nature?

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

Differential method for analysing the kinetic data is used

For a tubular flow reactor with uniform concentration and temperature, the independent variable is

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

In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO2 to SO3 is accomplished by a __________ reaction.

The catalyst in a first order chemical reaction changes the

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

For a tubular reactor with space time 'η' and residence time 'ζ', the following statement holds good.

For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of:

Kinetics of a solid catalysed reaction can best be studied in a __________ reactor.

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

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

Arrhenius equation represents graphically the variation between the __________ and temperature.

A rise in temperature

The extent of a reaction is

BET apparatus is used to determine the

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?

Effectiveness factor of a catalyst pellet is a measure of the __________ resistance.

Bulk diffusion in catalyst pore __________ with increase in pressure.

In the fluid catalytic cracker (FCC), the cracking reaction is __________ (i) and the regeneration is__________ (ii) __________.

Autocatalytic reactions are best carried out in a

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

Cold shot cooling is only practical when the feed temperature is __________ than the reaction temperature.

The rate constant of a reaction is a function of the

A plug-flow reactor is characterised by

The vessel dispersion number (D/μL) for plug flow is

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.

In the fluid catalytic cracker (FCC), the cracking reaction is (i) and the regeneration is (ii) __.