If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

If the catalyst pore size is small in comparison with the mean free
path, collisions with the pore wall controls the process'. The diffusivity
under this condition is called 'Knudsen diffusivity', which is affected by the
(A) Pressure
(B) Temperature
(C) Both (A) & (B)
(D) Neither (A) nor (B)
by

1 Answer

Answer :

(B) Temperature
by

Related questions

The Knudsen diffusivity is dependent on the (A) Molecular velocity only (B) Pore radius of the catalyst only (C) Molecular mean free path only (D) Molecular velocity and pore radius of the catalyst

Description : The Knudsen diffusivity is dependent on the (A) Molecular velocity only (B) Pore radius of the catalyst only (C) Molecular mean free path only (D) Molecular velocity and pore radius of the catalyst

Last Answer : (D) Molecular velocity and pore radius of the catalyst

Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as (A) DE = DM + DK (B) 1/DE = 1/DN + DK (C) DE = DM . DE (D) DE = DN/DE

Description : Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as (A) DE = DM + DK (B) 1/DE = 1/DN + DK (C) DE = DM . DE (D) DE = DN/DE

Last Answer : (B) 1/DE = 1/DN + DK

The Knudsen diffusivity is proportional to (where, T = absolute temperature) (A) √T (B) T 2 (C) T (D) T 4

Description : The Knudsen diffusivity is proportional to (where, T = absolute temperature) (A) √T (B) T 2 (C) T (D) T 4

Last Answer : (A) √T

With increase in temperature, the leaching rate increases because of the (A) Increased diffusivity (B) Decreased viscosity of liquid (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : With increase in temperature, the leaching rate increases because of the (A) Increased diffusivity (B) Decreased viscosity of liquid (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

With increase in temperature, the leaching rate increases due to (A) Decreased liquid viscosity (B) Increased diffusivity (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : With increase in temperature, the leaching rate increases due to (A) Decreased liquid viscosity (B) Increased diffusivity (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

Resistance to fusion of the refractory under a steady rising temperature condition is called (A) Spalling (B) Refractoriness (C) Both (A) & (B)(D) Neither (A) nor (B)

Description : Resistance to fusion of the refractory under a steady rising temperature condition is called (A) Spalling (B) Refractoriness (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Refractoriness

The importance of diffusion in a catalyst are increased by (A) Large catalyst particle size (B) An active surface of the catalyst (C) Small pore diameter (D) All (A), (B) and (C)

Description : The importance of diffusion in a catalyst are increased by (A) Large catalyst particle size (B) An active surface of the catalyst (C) Small pore diameter (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

In elastic collisions, A. only the total momentum of the colliding objects is conserved. B. only the total kinetic energy is conserved. C. both of the momentum and total kinetic energy are conserved. D. neither momentum of the colliding bodies nor the total kinetic energy are recoverable.

Description : In elastic collisions, A. only the total momentum of the colliding objects is conserved. B. only the total kinetic energy is conserved. C. both of the momentum and total kinetic energy ... D. neither momentum of the colliding bodies nor the total kinetic energy are recoverable.

Last Answer : both of the momentum and total kinetic energy are conserved.

Pick out the wrong statement. (A) Exit age description function (E) and internal age distribution function (I) are related as, E = -(dI/dθ) (B) Chemisorption studies are useful in the determination of catalyst surface area and pore size distribution (C) A higher temperature favours the reaction of higher activation energy (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products

Description : Pick out the wrong statement. (A) Exit age description function (E) and internal age distribution function (I) are related as, E = -(dI/dθ) (B) Chemisorption studies are useful in the ... energy (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products

Last Answer : (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products

Diffusivity in concentrated solutions differs from that in dilute solutions, because of the changes in (A) Viscosity with concentration (B) Degree of ideality of the solution (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Diffusivity in concentrated solutions differs from that in dilute solutions, because of the changes in (A) Viscosity with concentration (B) Degree of ideality of the solution (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

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) 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

Description : 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 ... (except the first one) is involved in each of the evaporation process (D) None of these

Last Answer : (B) There is no dynamic equilibrium between successive layer

Helium-mercury method is used for the measurement of the __________ of the catalyst. (A) Surface area (B) Porosity (C) Pore volume (D) Both (B) & (C)

Description : Helium-mercury method is used for the measurement of the __________ of the catalyst. (A) Surface area (B) Porosity (C) Pore volume (D) Both (B) & (C)

Last Answer : (D) Both (B) & (C)

Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the (A) Wall roughness (B) Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the (A) Wall roughness (B) Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

The main function of a muffle in the muffle furnace is to (A) Protect the charge from the effects of the products of combustion (B) Smooth out temperature inequalities on the combustion side of the muffle wall (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The main function of a muffle in the muffle furnace is to (A) Protect the charge from the effects of the products of combustion (B) Smooth out temperature inequalities on the combustion side of the muffle wall (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

The heating capacity of muffle furnace depends on the (A) Surface area & emissivity of the stock (B) Properties of the muffle wall (temperature, area, and emissivity) (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The heating capacity of muffle furnace depends on the (A) Surface area & emissivity of the stock (B) Properties of the muffle wall (temperature, area, and emissivity) (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

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

Description : 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 ... the catalyst diffusivity is reduced (D) Catalyst size is increased or the catalyst diffusivity is increased

Last Answer : (B) Catalyst size is reduced or the catalyst diffusivity is increased

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

Description : 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

Last Answer : (A) Specific surface of a porous catalyst

In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for (A) Fast reactions in catalyst of small pore diameter (B) Fast reaction in catalyst of large pore diameter (C) Slow reactions in catalyst of small pore diameter (D) Slow reactions in catalyst of large pore diameter

Description : In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for (A) Fast reactions in catalyst of small pore diameter (B) Fast reaction in catalyst ... reactions in catalyst of small pore diameter (D) Slow reactions in catalyst of large pore diameter

Last Answer : (C) Slow reactions in catalyst of small pore diameter

A catalyst in a chemical reaction __________ free energy change in the reaction. (A) Increases (B) Decreases (C) Either (A) or (B); depends on the type of catalyst (D) Neither (A) nor (B)

Description : A catalyst in a chemical reaction __________ free energy change in the reaction. (A) Increases (B) Decreases (C) Either (A) or (B); depends on the type of catalyst (D) Neither (A) nor (B)

Last Answer : (C) Either (A) or (B); depends on the type of catalyst

Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum (A) Flow rate (B) Mean velocity (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Description : Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum (A) Flow rate (B) Mean velocity (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Last Answer : (B) Mean velocity

Helium-mercury method can be used to determine the __________ of the catalyst particle. (A) Pore volume (B) Solid density (C) Porosity (D) All (A), (B), & (C)

Description : Helium-mercury method can be used to determine the __________ of the catalyst particle. (A) Pore volume (B) Solid density (C) Porosity (D) All (A), (B), & (C)

Last Answer : (D) All (A), (B), & (C)

Bulk diffusion in catalyst pore __________ with increase in pressure. (A) Increases (B) Decreases (C) Remains unchanged (D) Increases exponentially

Description : Bulk diffusion in catalyst pore __________ with increase in pressure. (A) Increases (B) Decreases (C) Remains unchanged (D) Increases exponentially

Last Answer : (B) Decreases

Pick out the correct statement. (A) A lower temperature favours the reaction of lower activation energy (B) The dispersion number for a reactor/vessel is uL/D (C) The rate controlling step in a reaction involving many steps is the fastest step (D) Pore volume and porosity of a catalyst is measured by Brunauer￾Emmett-Teller (BET) technique

Description : Pick out the correct statement. (A) A lower temperature favours the reaction of lower activation energy (B) The dispersion number for a reactor/vessel is uL/D (C) The rate controlling step in ... step (D) Pore volume and porosity of a catalyst is measured by Brunauer￾Emmett-Teller (BET) technique

Last Answer : (A) A lower temperature favours the reaction of lower activation energy

Concentration of H2SO4 catalyst in alkylation is kept between 90-98%, because H2SO4 having concentration. (A) Less than 90% promotes polymerisation (B) More than 98% promotes cracking (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Concentration of H2SO4 catalyst in alkylation is kept between 90-98%, because H2SO4 having concentration. (A) Less than 90% promotes polymerisation (B) More than 98% promotes cracking (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the __________ adsorption. (A) Physical (B) Chemical (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the __________ adsorption. (A) Physical (B) Chemical (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (B) Chemical

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)

Description : 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)

Last Answer : (D) All (A), (B) and (C)

An ideal nozzle design aims at (A) Minimising wall friction (B) Suppressing boundary layer separation (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : An ideal nozzle design aims at (A) Minimising wall friction (B) Suppressing boundary layer separation (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Fanning friction factor for laminar flow of fluid in a circular pipe is (A) Not a function of the roughness of pipe wall (B) Inversely proportional to Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Fanning friction factor for laminar flow of fluid in a circular pipe is (A) Not a function of the roughness of pipe wall (B) Inversely proportional to Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Gaseous diffusion co-efficient increases with increase in the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Gaseous diffusion co-efficient increases with increase in the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Temperature

Mass velocity in case of steady flow and through a constant cross￾section conduit is independent of the (A) Temperature (B) Pressure (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Mass velocity in case of steady flow and through a constant cross￾section conduit is independent of the (A) Temperature (B) Pressure (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Joule-Thomson co-efficient depends on the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Joule-Thomson co-efficient depends on the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Entropy of an ideal gas depends upon its (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Entropy of an ideal gas depends upon its (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

The internal energy of an incompressible fluid depends upon its (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The internal energy of an incompressible fluid depends upon its (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Temperature

The heat capacities for the ideal gas state depend upon the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The heat capacities for the ideal gas state depend upon the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Temperature

The direct shear test suffers from the following disadvantage: (A) Drain condition cannot be controlled (B) Pore water pressure cannot be measured (C) Shear stress on the failure plane is not uniform (D) The area under the shear and vertical loads does not remain constant throughout the test

Description : The direct shear test suffers from the following disadvantage: (A) Drain condition cannot be controlled (B) Pore water pressure cannot be measured (C) Shear stress on the failure plane is not uniform (D) The area under the shear and vertical loads does not remain constant throughout the test

Last Answer : Answer: Option C

In any spontaneous process, the __________ free energy decreases. (A) Helmholtz (B) Gibbs (C) Both ‘a’ & ‘b’ (D) Neither 'a' nor 'b'

Description : In any spontaneous process, the __________ free energy decreases. (A) Helmholtz (B) Gibbs (C) Both ‘a’ & ‘b’ (D) Neither 'a' nor 'b'

Last Answer : (C) Both ‘a’ & ‘b’

The main aspect of 'casual research' is ____________ 1. necessary condition 2. sufficient condition 3. both 1 & 2 4. neither 1 nor 2 5. none of these

Description : The main aspect of 'casual research' is ____________ 1. necessary condition 2. sufficient condition 3. both 1 & 2 4. neither 1 nor 2 5. none of these

Last Answer : both 1 & 2

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)

Description : 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)

Last Answer : (C) Both (A) and (B)

In a roll crusher, the specific power consumption and the production rate is affected by the (A) Reduction ratio (B) Differential roll speed (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : In a roll crusher, the specific power consumption and the production rate is affected by the (A) Reduction ratio (B) Differential roll speed (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

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)

Description : 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)

Last Answer : (D) All (A), (B) and (C)

If Thiele modulus is __________, then the pore diffusion resistance in a catalyst may be considered as negligible. (A) 0 (B) ∞ (C) < 0.5 (D) > 0.5

Description : If Thiele modulus is __________, then the pore diffusion resistance in a catalyst may be considered as negligible. (A) 0 (B) ∞ (C) < 0.5 (D) > 0.5

Last Answer : (C) < 0.5

If pore diffusion is the controlling step in a solid catalysed reaction, the catalyst (A) Porosity is very important (B) Porosity is of less importance (C) Internal surface area is utilised efficiently (D) None of these

Description : If pore diffusion is the controlling step in a solid catalysed reaction, the catalyst (A) Porosity is very important (B) Porosity is of less importance (C) Internal surface area is utilised efficiently (D) None of these

Last Answer : (B) Porosity is of less importance

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

Description : 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

Last Answer : (A) Pore diffusion

. 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)

Description : . 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)

Last Answer : (C) Surface area

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

Description : 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

Last Answer : (A) tan hT/T

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to (A) The intrinsic activation energy E (B) (E + ED) where ED is activation due to diffusion (C) (E + ED)/2 (D) ED/2

Description : If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to (A) The intrinsic activation energy E (B) (E + ED) where ED is activation due to diffusion (C) (E + ED)/2 (D) ED/2

Last Answer : (D) ED/2

For the flow of gases through a capillary, with increase in temperature, the permeability __________ as per Knudsen law. (A) Increases (B) Decreases (C) Remain same (D) Either (A) or (B); depends on the gas

Description : For the flow of gases through a capillary, with increase in temperature, the permeability __________ as per Knudsen law. (A) Increases (B) Decreases (C) Remain same (D) Either (A) or (B); depends on the gas

Last Answer : (A) Increases

The mechanism of size reduction by a hammer mill is by impact and attrition between the (A) Grinding element & the housing (B) Feed particles (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : The mechanism of size reduction by a hammer mill is by impact and attrition between the (A) Grinding element & the housing (B) Feed particles (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

Width and speed of a conveyor belt depends upon the __________ of the material. (A) Lump size (B) Bulk density (C) Both (A) & (B) (D) Neither (A) nor (B

Description : Width and speed of a conveyor belt depends upon the __________ of the material. (A) Lump size (B) Bulk density (C) Both (A) & (B) (D) Neither (A) nor (B

Last Answer : (C) Both (A) & (B)