For series reaction, the relative yield__________________?

Is always greater for plug-flow reactor than for the single CSTR of the same volume

Decreases with increasing conversion

For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a_________________?

Single CSTR is the most suitable

Batch reactor is preferred over a single CSTR for high yield

Tubular reactor is preferred over a single CSTR for high yield

Single CSTR is the most suitable

For multiple reactions, the flow pattern within the vessel affects the ____________________?

Distribution of reaction products

For high conversion in a highly exothermic solid catalysed reaction, use a ______________ bed reactor?

Fixed bed reactor followed by a fluidised

Fluidised bed reactor followed by a fixed

Fixed bed reactor followed by a fluidised

For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?

[CA0/(1 + εA XA)] (dXA/dt) = k

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

For all positive reaction orders for a particular duty ?

Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

Mixed reactor is always larger than the plug-flow reactor

Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

Reactor size is independent of the type of flow

Density variation during reaction affects design

For a zero order reaction, the concentration of product increases with the _____________________?

Increase in initial concentration

For a zero order chemical reaction, the__________________?

Half life period is directly proportion to the initial concentration of the reactants

Plot of products concentration with time is a straight line through the origin

Products concentration increases linearly with time

For a vapour phase catalytic reaction (A + B → P) which follows the Ridel mechanism and the reaction step is rate controlling, the rate of reaction is given by (reaction rate is irreversible, product also absorbs) ?

-rA = (k . PA 2 – k1PP)/(1 + KAPA + KPPP)

-rA = (k . PA . PB)/(1 + KAPA + KPPP)

-rA = (k . PA 2 – k1PP)/(1 + KAPA + KPPP)

-rA = (k . PA . PB)/(1 + KAPB + KBPB . KPPP)

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

For a heterogeneous 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

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 importa

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 importa

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 a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the____________________?

Catalyst size is increased or the catalyst diffusivity is reduced

Catalyst size is reduced or the catalyst diffusivity is reduced

Catalyst size is reduced or the catalyst diffusivity is increased

Catalyst size is increased or the catalyst diffusivity is reduced

Catalyst size is increased or the catalyst diffusivity is increased

409 + Mcqs in Chemical Reaction in Chemical Engineering Page 6 McqOptions

251.	_____________ gas is normally employed in B.E.T. method of finding out the surface area of catalyst?
A.	N2
B.	H2
C.	CO2
D.	He
Answer» B. H2

252.	From collision theory, the reaction rate constant is proportional to_________________?
A.	exp (-E/RT)
B.	exp (-E/2RT)
C.	√T
D.	Tm exp (-E/RT)
Answer» E.

253.	From Arrhenius 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___________________?
A.	k cal
B.	k cal/°K
C.	°K
D.	k cal. °K
Answer» D. k cal. °K

254.	From among the following, choose one which is not an exothermic process ?
A.	Methanol synthesis
B.	Catalytic cracking
C.	Ammonia synthesis
D.	Oxidation of sulphur
Answer» C. Ammonia synthesis

255.	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

256.	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

257.	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

258.	For the reaction as shown in the bellow figure, the rate of formation of Z is 0.2 gm mole/litre.hr. What is the rate of disappearance of X in gm mole/litre.hr ?
A.	0.4
B.	0.1
C.	0.2
D.	None of these
Answer» B. 0.1

259.	For the reaction, A + B → 2B + C,___________________?
A.	rA = rB
B.	rA = -rB
C.	rA = 2rB
D.	rA = rB/2
Answer» C. rA = 2rB

260.	For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the _______________ is the controlling resistance?
A.	Film diffusion
B.	Diffusion through ash layer
C.	Chemical reaction
D.	Either A., B. or C.
Answer» C. Chemical reaction

261.	For the non catalytic reaction of particles with surrounding fluid, the same needed to achieve the same fractional conversion for particles of different unchanging sizes is proportional to the particle diameter, when the ________________ is the controlling resistance?
A.	Film diffusion
B.	Diffusion through ash layer
C.	Chemical reaction
D.	Either A., B. or C.
Answer» D. Either A., B. or C.

263.	For the liquid phase parallel reactions__________________?_x005F_x000D_R, rR = K1.CA2; E1 = 80 KJ/mole_x005F_x000D_S, rs = K1.CA ; E2 = 120 KJ/mole_x005F_x000D_The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at
A.	Low temperature in a CSTR
B.	High temperature in a CSTR
C.	Low temperature in a PFR
D.	High temperature in a PFR
Answer» E.

264.	For the irreversible elementary reactions in parallel as shown in the bellow figure, the rate of disappearance of ‘X’ is equal to_______________?
A.	CA (K1 + K2)
B.	CA (K1 + K2)/2
C.	CA . K1/2
D.	CA . K2/2
Answer» B. CA (K1 + K2)/2

276.	For any reaction, we may write conversion as a function of______________________?
A.	Time
B.	Temperature
C.	Concentration
D.	All A., B. & C.
Answer» E.

279.	For an ideal plug flow reactor, the value of Peclet number is_______________?
A.	0
B.	1
C.	10
D.	∞
Answer» B. 1

262.	For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR ?
A.	0.15
B.	0.30
C.	0.60
D.	0.90
Answer» D. 0.90

265.	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

266.	For the chemical reaction X → Y, it is observed that, on doubling the concentration of ‘X’, the reaction rate quadruples. If the reaction rate is proportional to Cx n, then what is the value of „n‟ ?
A.	1/4
B.	2
C.	4
D.	16
Answer» D. 16

267.	For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of ‘P’ is doubled. If the reaction rate is proportional to Cp n, then what is the value of ‘n’ for this chemical reaction ?
A.	0
B.	1
C.	2
D.	3
Answer» C. 2

268.	For series reaction, the relative yield__________________?
A.	Is always greater for plug-flow reactor than for the single CSTR of the same volume
B.	Statement in A. is wrong
C.	Decreases with increasing conversion
D.	Both A. and C. hold good
Answer» E.

269.	For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a_________________?
A.	Batch reactor is preferred over a single CSTR for high yield
B.	Tubular reactor is preferred over a single CSTR for high yield
C.	Both A. and B.
D.	Single CSTR is the most suitable
Answer» D. Single CSTR is the most suitable

270.	For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a _________________ reactor?
A.	Stirred tank
B.	Tubular flow
C.	Batch
D.	Fixed bed
Answer» B. Tubular flow

271.	For multiple reactions, the flow pattern within the vessel affects the ____________________?
A.	Size requirement
B.	Distribution of reaction products
C.	Both A. and B.
D.	Neither A. nor B.
Answer» D. Neither A. nor B.

272.	For identical flow rate, feed composition and for elementary first order reactions, ‘N’ equal sized mixed reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for constant density systems. This is true, when the value of ‘N’ is ___________________?
A.	1
B.	> 1
C.	∞
D.	≥ 1
Answer» D. ≥ 1

273.	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

Explore topic-wise MCQs in Chemical Engineering.

_____________ gas is normally employed in B.E.T. method of finding out the surface area of catalyst?

From collision theory, the reaction rate constant is proportional to_________________?

From Arrhenius 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___________________?

From among the following, choose one which is not an exothermic process ?

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

Fractional conversion _________________ for an exothermic reversible chemical reaction, when the temperature is maximum?

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 ?

For the reaction as shown in the bellow figure, the rate of formation of Z is 0.2 gm mole/litre.hr. What is the rate of disappearance of X in gm mole/litre.hr ?

For the reaction, A + B → 2B + C,___________________?

For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the _______________ is the controlling resistance?

For the non catalytic reaction of particles with surrounding fluid, the same needed to achieve the same fractional conversion for particles of different unchanging sizes is proportional to the particle diameter, when the ________________ is the controlling resistance?

For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR ?

For the liquid phase parallel reactions__________________?_x005F_x000D_R, rR = K1.CA2; E1 = 80 KJ/mole_x005F_x000D_S, rs = K1.CA ; E2 = 120 KJ/mole_x005F_x000D_The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at

For the irreversible elementary reactions in parallel as shown in the bellow figure, the rate of disappearance of ‘X’ is equal to_______________?

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

For the chemical reaction X → Y, it is observed that, on doubling the concentration of ‘X’, the reaction rate quadruples. If the reaction rate is proportional to Cx n, then what is the value of „n‟ ?

For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of ‘P’ is doubled. If the reaction rate is proportional to Cp n, then what is the value of ‘n’ for this chemical reaction ?

For series reaction, the relative yield__________________?

For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a_________________?

For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a _________________ reactor?

For multiple reactions, the flow pattern within the vessel affects the ____________________?

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 high conversion in a highly exothermic solid catalysed reaction, use a ______________ bed reactor?

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?

For any reaction, we may write conversion as a function of______________________?

For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?

For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is____________________?

For an ideal plug flow reactor, the value of Peclet number is_______________?

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

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

For an autocatalytic reactor, the suitable reactor set up is__________________?

For all positive reaction orders for a particular duty ?

For a zero order reaction, the concentration of product increases with the _____________________?

For a zero order chemical reaction, the__________________?

For a vapour phase catalytic reaction (A + B → P) which follows the Ridel mechanism and the reaction step is rate controlling, the rate of reaction is given by (reaction rate is irreversible, product also absorbs) ?

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

For a tubular reactor with space time ‘η’ and residence time ‘ζ’, the following statement holds good ?

For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the ______________ adsorption?

For a reaction of the type of bellow given figure, the rate of reaction (- rx) is given by___________________?

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

For a _____________ order reaction, the units of rate constant and rate of reaction are the same ?

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

For a homogeneous reaction of nth order, the dimension of the rate constant is given by_________________?

For a heterogeneous 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______________________?

For a heterogeneous catalytic reaction____________________?

For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be ______________ times?

For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the____________________?

For a first order reaction carried out in a plug flow reactor, the space time is__________________?

For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to ____________________?

274.	For high conversion in a highly exothermic solid catalysed reaction, use a ______________ bed reactor?
A.	Fixed
B.	Fluidised bed reactor followed by a fixed
C.	Fixed bed reactor followed by a fluidised
D.	Fluidised
Answer» C. Fixed bed reactor followed by a fluidised

275.	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

277.	For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?
A.	XA = k . t
B.	[CA0/(1 + εA XA)] (dXA/dt) = k
C.	-ln(1 – XA) = kt
D.	εA . ln (1 – XA) = k . t
Answer» C. -ln(1 – XA) = kt

278.	For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is____________________?
A.	2
B.	4
C.	11
D.	22
Answer» D. 22

280.	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.

281.	For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant ?
A.	Is independent of pressure
B.	Increases with pressure
C.	Decreases with pressure
D.	Increases /decreases with pressure depending on the stoichiometric co-efficients of the reaction
Answer» C. Decreases with pressure

282.	For an autocatalytic reactor, the suitable reactor set up is__________________?
A.	P.F. reactors in series
B.	CSTR in series
C.	CSTR followed by P.F. reactor
D.	P.F. reactor followed by CSTR
Answer» D. P.F. reactor followed by CSTR

283.	For all positive reaction orders for a particular duty ?
A.	Mixed reactor is always larger than the plug-flow reactor
B.	Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order
C.	Reactor size is independent of the type of flow
D.	Density variation during reaction affects design
Answer» B. Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

284.	For a zero order reaction, the concentration of product increases with the _____________________?
A.	Increase of reaction time
B.	Increase in initial concentration
C.	Total pressure
D.	Decrease in total pressure
Answer» B. Increase in initial concentration

285.	For a zero order chemical reaction, the__________________?
A.	Half life period is directly proportion to the initial concentration of the reactants
B.	Plot of products concentration with time is a straight line through the origin
C.	Products concentration increases linearly with time
D.	All A., B. and C.
Answer» E.