8247 + Mcqs in Chemical Engineering Page 95 McqOptions

4701.	Carrier in a catalyst increases its
A.	surface area
B.	activity
C.	performance
D.	none of these
Answer» B. activity

Discussion

4702.	When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value.
A.	twice
B.	half
C.	equal
D.	none of these
Answer» C. equal

Discussion

4703.	An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time.
A.	increase
B.	increase exponentially
C.	decrease
D.	remain unchanged
Answer» D. remain unchanged

Discussion

4704.	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

4705.	The role of a catalyst in a chemical reaction is to change the
A.	equilibrium constant
B.	activation energy
C.	final products
D.	heat of reaction
Answer» C. final products

Discussion

4706.	The vessel dispersion number (D/ L) for plug flow is
A.	0
B.	500
C.	750
D.
Answer» B. 500

Discussion

4707.	Molecularity of a reaction
A.	is always equal to the overall order of reaction.
B.	may not be equal to the order of reaction.
C.	can't have a fractional value.
D.	both (b) and (c).
Answer» E.

Discussion

4708.	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

4709.	The exit age distribution of fluid leaving a vessel is used to know the
A.	activation energies of a reaction.
B.	reaction mechanism.
C.	extent of non-ideal flow in the vessel.
D.	none of these.
Answer» D. none of these.

Discussion

4710.	In the converter of the contact process for the manufacture of H2SO4 the equilibrium conversion of SO2 __________ (A) __________ with increase in temperature and __________ (B) __________ with increase in the mole ratio of SO2 to air.
A.	(A) increases (B) decreases
B.	(A) decreases (B) increases
C.	(A) increases (B) increases
D.	(A) decreases (B) decreases
Answer» C. (A) increases (B) increases

Discussion

4711.	Pick the WRONG design guideline for a reactor in which the reactions, A R (desired) and A S (undesired) are to take place. The ratio of the reaction rates is .
A.	use high pressure and eliminate inerts, when a > b.
B.	avoid recycle, when a > b.
C.	use batch reactor or plug flow reactor, when a > b.
D.	use CSTR with a high conversion, when a > b.
Answer» C. use batch reactor or plug flow reactor, when a > b.

Discussion

4712.	With increase in temperature, the equilibrium __________ rises in case of endothermic reaction.
A.	constant
B.	conversion
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» C. both (a) & (b)

Discussion

4713.	In case of a consecutive unimolecular type first order reaction , the concentration of component __________ increases continuously with time.
A.	<i>S</i>
B.	<i>R</i>
C.	<i>A</i>
D.	none of these
Answer» B. <i>R</i>

Discussion

4714.	Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in
A.	blood
B.	saliva
C.	intestine
D.	gland
Answer» C. intestine

Discussion

4715.	Considering the endotheomic dissociation of CaCO3 in a closed vessel (CaCO3 CaO + CO2), the pressure of CO2 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.

Discussion

4716.	A catalyst in a chemical reaction
A.	decreases the activation energy.
B.	alters the reaction mechanism.
C.	increases the frequency of collisions of reacting species.
D.	all (a), (b) and (c).
Answer» E.

Discussion

4717.	In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants)
A.	A
B.	N
C.	A+N
D.	A-N
Answer» D. A-N

Discussion

4718.	Thermodynamic equilibrium constant in a system is affected by
A.	inerts
B.	pressure
C.	temperature
D.	all (a), (b) & (c)
Answer» D. all (a), (b) & (c)

Discussion

4719.	The most suitable reactor for carrying out an auto-thermal reaction is a
A.	batch reactor
B.	CSTR
C.	semi-batch reactor
D.	plug-flow reactor
Answer» C. semi-batch reactor

Discussion

4720.	Limiting reactant in a chemical reaction decides the
A.	rate constant
B.	conversion
C.	reaction speed
D.	equilibrium constant.
Answer» C. reaction speed

Discussion

4721.	The rate of forward reaction, at chemical equilibrium is____the rate of backward reaction.
A.	more than
B.	less than
C.	equal to
D.	either (b) or (c)
Answer» D. either (b) or (c)

Discussion

4722.	A balanced chemical reaction equation conforms to the law of
A.	conservation of mass
B.	Avagadro's hypothesis
C.	gaseous volumes
D.	none ofthese
Answer» B. Avagadro's hypothesis

Discussion

4723.	An exothermic reaction takes place in an adiabatic reactor. The product temperature __________ reactor feed temperature.
A.	is always equal to
B.	is always greater than
C.	is always less than
D.	may be greater or less than
Answer» C. is always less than

Discussion

4724.	Reverse reaction in a chemical equilibrium is favoured by the
A.	removal of one of the products regularly.
B.	increase in the concentration of oneof the products.
C.	increase in the concentration of one of the reactants.
D.	none of these.
Answer» C. increase in the concentration of one of the reactants.

Discussion

4725.	The equilibrium constant for the reversible reaction, , is affected by the
A.	temperature of the system.
B.	presence or absence of inerts.
C.	pressure of the system.
D.	kinetics of the reaction.
Answer» D. kinetics of the reaction.

Discussion

4726.	Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction.
A.	order
B.	overall order
C.	molecularity
D.	none of these
Answer» C. molecularity

Discussion

4727.	Catalyst is a substance, which __________ chemical reaction.
A.	increases the speed of a
B.	decreases the speed of a
C.	can either increase or decrease the speed of a
D.	alters the value of equilibrium constant in a reversible
Answer» D. alters the value of equilibrium constant in a reversible

Discussion

4728.	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

4729.	The enzyme which can catalyse the conversion of glucose to ethyl alcohol is
A.	invertase
B.	maltase
C.	diastase
D.	zymase
Answer» E.

Discussion

4730.	The equilibrium constant of chemical reaction __________ in the presence of catalyst.
A.	increases
B.	decreases
C.	remains unaffected
D.	can either increase or decrease (depends on the type of catalyst)
Answer» D. can either increase or decrease (depends on the type of catalyst)

Discussion

4731.	The order of a chemical reaction is
A.	an experimentally determined quantity.
B.	always equal to the total stoichiometric number of reactants.
C.	never fractional.
D.	none of these.
Answer» B. always equal to the total stoichiometric number of reactants.

Discussion

4732.	A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction.
A.	less than
B.	equal to
C.	more than
D.	equal to or more than
Answer» E.

Discussion

4733.	Overall rate of reaction in a heterogenous 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

4734.	__________ resistance is not involved in the combustion of a carbon particle.
A.	Gas film
B.	Ash
C.	Chemical reaction
D.	none of these
Answer» C. Chemical reaction

Discussion

4735.	In an ideal P.F.R. at steady state conditions
A.	the composition of reactants remains constant along a flow path.
B.	the conversion of the reactant varies from point to point along a flow path.
C.	there is no lateral mixing of fluid.
D.	there may be diffusion along the flow path.
Answer» C. there is no lateral mixing of fluid.

Discussion

4736.	The reaction rate constants at two different temperature T1 and T2 are related by
A.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/470-421-1.png">
B.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/470-421-2.png">
C.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/470-421-3.png">
D.	<img src="/_files/images/chemical-engineering/chemical-reaction-engineering/470-421-4.png">
Answer» C. <img src="/_files/images/chemical-engineering/chemical-reaction-engineering/470-421-3.png">

Discussion

4737.	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

4738.	The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are
A.	2 & 1
B.	11 & 2
C.	2 && 2
D.	1 & 1
Answer» B. 11 & 2

Discussion

4739.	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

4740.	Following isothermal kinetic data are obtained in a basket type of mixed flow reactor for a porous catalyst. Determine the role of pore diffusion and external mass transfer processes.
A.	Strong pore diffusion control and mass transfer not controlling.
B.	Both pore diffusion and mass transfer not controlling.
C.	Both pore diffusion and mass transfer controlling.
D.	Mass transfer controlling.
Answer» B. Both pore diffusion and mass transfer not controlling.

Discussion

4741.	The irreversible reaction is a special case of reversible reaction, if the
A.	equilibrium constant is 1.
B.	conversion of the reactant at equilibrium condition is zero.
C.	reactant concentration at equilibrium condition is zero.
D.	all (a), (b) and (c).
Answer» D. all (a), (b) and (c).

Discussion

4742.	A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m3 and volumetric flow rate 1m3 /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m3 . The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 kmole/m3 , the volume of the mixed flow reactor should be increased by a factor of
A.	7
B.	6
C.	3
D.	7/3
Answer» B. 6

Discussion

4743.	For the liquid phase parallel reactions:R, rR = K1.CA2; E1 = 80 KJ/moleS, rs = K1.CA ; E2 = 120 KJ/mole 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.

Discussion

4744.	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

4745.	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

Discussion

4746.	For a fluidised bed reactor, the most suitable/relevant model is a __________ model.
A.	tank in series
B.	bubbling bed
C.	plug flow
D.	none of these
Answer» C. plug flow

Discussion

4747.	The conversion for a first order liquid phase reaction. A B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be
A.	60
B.	75
C.	90
D.	100
Answer» C. 90

Discussion

4748.	What is the dispersion number for a CSTR?
A.	0
B.	1
C.	< 1
D.
Answer» E.

Discussion

4749.	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

4750.	With increase in temperature, the rate constant obeying Arhenious equation
A.	increases.
B.	decreases.
C.	decreases exponentially.
D.	can either increase or decrease ; depends on the frequency factor.
Answer» B. decreases.

Discussion

Explore topic-wise MCQs in Engineering.

Carrier in a catalyst increases its

When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value.

An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time.

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 role of a catalyst in a chemical reaction is to change the

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

Molecularity of a reaction

BET apparatus is used to determine the

The exit age distribution of fluid leaving a vessel is used to know the

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

Pick the WRONG design guideline for a reactor in which the reactions, A R (desired) and A S (undesired) are to take place. The ratio of the reaction rates is .

With increase in temperature, the equilibrium __________ rises in case of endothermic reaction.

In case of a consecutive unimolecular type first order reaction , the concentration of component __________ increases continuously with time.

Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in

Considering the endotheomic dissociation of CaCO3 in a closed vessel (CaCO3 CaO + CO2), the pressure of CO2 increases, if

A catalyst in a chemical reaction

In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants)

Thermodynamic equilibrium constant in a system is affected by

The most suitable reactor for carrying out an auto-thermal reaction is a

Limiting reactant in a chemical reaction decides the

The rate of forward reaction, at chemical equilibrium is____the rate of backward reaction.

A balanced chemical reaction equation conforms to the law of

An exothermic reaction takes place in an adiabatic reactor. The product temperature __________ reactor feed temperature.

Reverse reaction in a chemical equilibrium is favoured by the

The equilibrium constant for the reversible reaction, , is affected by the

Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction.

Catalyst is a substance, which __________ chemical reaction.

A rise in temperature

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

The equilibrium constant of chemical reaction __________ in the presence of catalyst.

The order of a chemical reaction is

A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction.

Overall rate of reaction in a heterogenous 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.

__________ resistance is not involved in the combustion of a carbon particle.

In an ideal P.F.R. at steady state conditions

The reaction rate constants at two different temperature T1 and T2 are related by

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

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

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

Following isothermal kinetic data are obtained in a basket type of mixed flow reactor for a porous catalyst. Determine the role of pore diffusion and external mass transfer processes.

The irreversible reaction is a special case of reversible reaction, if the

For the liquid phase parallel reactions:R, rR = K1.CA2; E1 = 80 KJ/moleS, rs = K1.CA ; E2 = 120 KJ/mole The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at

Design of heterogeous catalytic reactor involves consideration of __________ steps.

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 ?

For a fluidised bed reactor, the most suitable/relevant model is a __________ model.

The conversion for a first order liquid phase reaction. A B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be

What is the dispersion number for a CSTR?

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

With increase in temperature, the rate constant obeying Arhenious equation

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