Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3 /sec. V = volume, cm3 .)

Reactor dispersion number (D/vL)

A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is

d(VCA)/dt = -F (CAF - CA) - kCA 2V

d(VCA)/dt = F (CAF - CA) - kCA 2V

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

Batch process is preferred over continuous process, when the

Product yields and quality cannot be achieved in continuous process, because of long residence time

Sales demand of product is not steady

Same equipment cannot be used for several processes of the same nature

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

Averaged over the inlet and outlet

Rate of a chemical reaction is not affected by the

Number of molecules of reactants taking part in the reaction

On application of pressure to the equilibrium system, ice ⇌ water; which of the following phenomenon will occur?

Equilibrium will not be attained

In an exothermic reaction, the energy of the reacting substances as compared to that of products is

Either (A) or (B), depends on order of reaction

Semibatch reactor is preferred, when a/an

A highly exothermic reaction is to be controlled

Undesirable side reaction (at high concentration of one of the reactants) is to be avoided

A gas is to be reacted with liquid (e.g. hydrogenation of fat)

Depends on the mechanism of reaction only

Depends on both pressure and mechanism of reaction

Is independent of the mechanism of reaction

Describes the extensive operating characteristics of a tubular flow reactor

Is the maximum feed rate per unit volume of reactor for a given conversion

Is a measure of the ease of the reaction

Variables affecting the rate of homogeneous reactions are

Temperature and composition only

Pressure, temperature and composition

In a zero order reaction, reactants concentration does not change with time and the

Time for half change is independent of the initial concentration

Time for half change is half the time taken for completion of the reaction

Time for half change is independent of the initial concentration

Time for completion of the reaction is independent of the initial concentration

Reaction rate is trebled when the initial concentration is trebled

For the same residence time, which one will give the maximum conversion?

Single stirred tank (v = 5 litres)

Two stirred tank (each of 2.5 litres) in series

Stirred tank followed by tubular flow reactor (each of 2.5 litres)

Single tubular flow reactor (v = 5 litres)

In case of the irreversible unimolecular type, first order reaction, the fractional conversion at any time for constant volume system as compared to variable volume system is

Either (A) or (B), depends on other factors

'Unreacted core model' represents the reaction involving

Manufacture of carbon disulphide from elements

Brunauer, 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?

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

Langmuirs assumption applies to every adsorbed layer

There is no dynamic equilibrium between successive layer

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

A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are

Of such size that the ratio of their volumes is < 5

A stirred tank reactor compared to tubular-flow reactor provides

More uniform operating conditions

Permits operation at the optimum temperature for a long reaction time

Higher overall selectivity for a first order consecutive reaction

A photochemical reaction is __________ light.

Used to convert heat energy into

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.

Data insufficient; cant be predicted

1443 + Mcqs in Chemical Reaction Engineering in Chemical Engineering Page 29 McqOptions

1401.	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

1402.	The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst.
A.	Increases
B.	Decreases
C.	Remain unaffected
D.	Unpredictable from the data
Answer» D. Unpredictable from the data

1403.	Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17 the KP for the reaction CO + H2O = CO2 + H2 is
A.	103.01
B.	10-0.67
C.	10-3.01
D.	100.67
Answer» E.

1404.	Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3 /sec. V = volume, cm3 .)
A.	Reactor dispersion number (D/vL)
B.	Reduced time (vt/V)
C.	Thiele modulus L √(k/D1)
D.	None of these
Answer» E.

1405.	A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is
A.	d(VCA)/dt = -F (CAF - CA) - kCA 2V
B.	d(VCA)/dt = F (CAF - CA) - kCA 2V
C.	d(VCA)/dt = -FCA - kCA 2V
D.	d(VCA)/dt = FCAF - kCA 2V
Answer» E.

1406.	The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line?
A.	XA Vs . η
B.	XA Vs ln η
C.	XA/(1 - XA)Vs η
D.	XA(1 - XA)Vs η
Answer» B. XA Vs ln η

1407.	For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the
A.	Catalyst size is reduced or the catalyst diffusivity is reduced
B.	Catalyst size is reduced or the catalyst diffusivity is increased
C.	Catalyst size is increased or the catalyst diffusivity is reduced
D.	Catalyst size is increased or the catalyst diffusivity is increased
Answer» C. Catalyst size is increased or the catalyst diffusivity is reduced

1408.	Batch process is preferred over continuous process, when the
A.	Product yields and quality cannot be achieved in continuous process, because of long residence time
B.	Sales demand of product is not steady
C.	Same equipment cannot be used for several processes of the same nature
D.	All (A), (B) & (C)
Answer» E.

1409.	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

1410.	Rate of a chemical reaction is not affected by the
A.	Catalyst
B.	Temperature
C.	Reactant’s concentration
D.	Number of molecules of reactants taking part in the reaction
Answer» E.

1411.	Molecularity of an elementary reaction, P + Q → R + S is
A.	1
B.	2
C.	3
D.	4
Answer» E.

1413.	The exit age distribution of a fluid leaving a vessel (denoted by E) is used to study the extent of non-ideal flow in the vessel. The value of ∫ ∞ 0 E.dt is
A.	0
B.	1
C.	∞
D.	√2π
Answer» C. ∞

1415.	Effectiveness factor (E) of a catalyst pellet is defined as, E = (actual rate within pore of the catalyst)/(rate if not snowed by pore diffusion), Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus)
A.	tan hT/T
B.	tan T/T
C.	tan hT/tan T
D.	None of these
Answer» B. tan T/T

1417.	Photo-chemical reactions occur in presence of
A.	Sunlight
B.	Darkness
C.	Solid catalysts
D.	Monochromatic radiation only
Answer» B. Darkness

1422.	If a solid-gas non-catalytic reaction occurs at very high temperature, the rate controlling step is the __________ diffusion.
A.	Film
B.	Ash layer
C.	Pore
D.	None of these
Answer» B. Ash layer

1412.	On application of pressure to the equilibrium system, ice ⇌ water; which of the following phenomenon will occur?
A.	Water will evaporate
B.	Equilibrium will not be attained
C.	More ice will be formed
D.	More water will be formed
Answer» E.

1414.	B.E.T. method can be used to determine the __________ of a porous catalyst
A.	Solid density
B.	Pore volume
C.	Surface area
D.	All (A), (B) and (C)
Answer» D. All (A), (B) and (C)

1416.	In an exothermic reaction, the energy of the reacting substances as compared to that of products is
A.	More
B.	Less
C.	Same
D.	Either (A) or (B), depends on order of reaction
Answer» B. Less

1418.	Semibatch reactor is preferred, when a/an
A.	A highly exothermic reaction is to be controlled
B.	Undesirable side reaction (at high concentration of one of the reactants) is to be avoided
C.	A gas is to be reacted with liquid (e.g. hydrogenation of fat)
D.	All (A), (B), and (C)
Answer» E.

1419.	The conversion of a reactant, undergoing a first order reaction, at a time equal to three times the half life of the reaction is:
A.	0.875
B.	0.5
C.	0.425
D.	Data insufficient to calculate
Answer» B. 0.5

1420.	The heat of reaction
A.	Depends on the pressure only
B.	Depends on the mechanism of reaction only
C.	Depends on both pressure and mechanism of reaction
D.	Is independent of the mechanism of reaction
Answer» E.

1421.	Space velocity
A.	Describes the extensive operating characteristics of a tubular flow reactor
B.	Is the maximum feed rate per unit volume of reactor for a given conversion
C.	Is a measure of the ease of the reaction
D.	All (A), (B) and (C)
Answer» E.

1423.	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.

1424.	Variables affecting the rate of homogeneous reactions are
A.	Pressure and temperature only
B.	Temperature and composition only
C.	Pressure and composition only
D.	Pressure, temperature and composition
Answer» E.

1425.	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

Explore topic-wise MCQs in Chemical Engineering.

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

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

Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17 the KP for the reaction CO + H2O = CO2 + H2 is

Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3 /sec. V = volume, cm3 .)

The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line?

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

Batch process is preferred over continuous process, when the

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

Rate of a chemical reaction is not affected by the

Molecularity of an elementary reaction, P + Q → R + S is

On application of pressure to the equilibrium system, ice ⇌ water; which of the following phenomenon will occur?

The exit age distribution of a fluid leaving a vessel (denoted by E) is used to study the extent of non-ideal flow in the vessel. The value of ∫ ∞ 0 E.dt is

B.E.T. method can be used to determine the __________ of a porous catalyst

Effectiveness factor (E) of a catalyst pellet is defined as, E = (actual rate within pore of the catalyst)/(rate if not snowed by pore diffusion), Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus)

In an exothermic reaction, the energy of the reacting substances as compared to that of products is

Photo-chemical reactions occur in presence of

Semibatch reactor is preferred, when a/an

The conversion of a reactant, undergoing a first order reaction, at a time equal to three times the half life of the reaction is:

The heat of reaction

Space velocity

If a solid-gas non-catalytic reaction occurs at very high temperature, the rate controlling step is the __________ diffusion.

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

Variables affecting the rate of homogeneous reactions are

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

In a zero order reaction, reactants concentration does not change with time and the

For the same residence time, which one will give the maximum conversion?

In case of the irreversible unimolecular type, first order reaction, the fractional conversion at any time for constant volume system as compared to variable volume system is

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

'Unreacted core model' represents the reaction involving

Brunauer, 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?

The value of Steric factor 'P' in the equation k = PZe E/RT usually ranges from

An example of autothermal reactor operation is

Half life period of a first order irreversible reaction A → B is

A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are

A stirred tank reactor compared to tubular-flow reactor provides

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

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

Fluid flow in a real packed bed can be approximated as __________ model

A photochemical reaction is __________ light.

Participation of __________ is involved in the occurrence of a chemical reaction

An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will

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.

1426.	In a zero order reaction, reactants concentration does not change with time and the
A.	Time for half change is half the time taken for completion of the reaction
B.	Time for half change is independent of the initial concentration
C.	Time for completion of the reaction is independent of the initial concentration
D.	Reaction rate is trebled when the initial concentration is trebled
Answer» B. Time for half change is independent of the initial concentration

1427.	For the same residence time, which one will give the maximum conversion?
A.	Single stirred tank (v = 5 litres)
B.	Two stirred tank (each of 2.5 litres) in series
C.	Stirred tank followed by tubular flow reactor (each of 2.5 litres)
D.	Single tubular flow reactor (v = 5 litres)
Answer» E.

1428.	In case of the irreversible unimolecular type, first order reaction, the fractional conversion at any time for constant volume system as compared to variable volume system is
A.	More
B.	Less
C.	Same
D.	Either (A) or (B), depends on other factors
Answer» D. Either (A) or (B), depends on other factors

1429.	The effectiveness factor for large value of Thiele modulus [L√(K/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/[L√(K/D1)]
C.	1
D.	∞
Answer» C. 1

1430.	'Unreacted core model' represents the reaction involving
A.	Combustion of coal particles
B.	Roasting of sulphide ores
C.	Manufacture of carbon disulphide from elements
D.	None of these
Answer» C. Manufacture of carbon disulphide from elements

1431.	Brunauer, 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.	Langmuirs 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

1432.	The value of Steric factor 'P' in the equation k = PZe E/RT usually ranges from
A.	1.0 to 10-8
B.	1.1 to 102
C.	0.1 to 0.9
D.	None of these
Answer» B. 1.1 to 102

1433.	An example of autothermal reactor operation is
A.	Sulphur dioxide oxidation
B.	Ethylene oxidation
C.	Benzene oxidation
D.	Ammonia synthesis
Answer» C. Benzene oxidation

1434.	Half life period of a first order irreversible reaction A → B is
A.	k/2
B.	ln k/2
C.	ln 2/k
D.	ln 0.5/k
Answer» D. ln 0.5/k

1435.	A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are
A.	Equal in size
B.	Of different sizes
C.	Of such size that the ratio of their volumes is < 5
D.	None of these
Answer» B. Of different sizes