Mass Transfer MCQs

Option A: Large surface per unit volume

Option B: Large free cross-section

Option C: Low weight per unit volume

Option D: Large weight of liquid retained

Correct Answer: Large weight of liquid retained ✔

Option A: Lewis relationship

Option B: Galileo number

Option C: Weber number

Option D: Dean number

Correct Answer: Lewis relationship ✔

Option A: 1

Option B: 0

Option C: ∞

Option D: None of these

Correct Answer: ∞ ✔

Option A: Caustic solution

Option B: Dilute ammoniacal liquor

Option C: Dilute HCl

Option D: Ethanolamine

Correct Answer: Dilute ammoniacal liquor ✔

Option A: No change in theoretical

Option B: Marginal decrease in the number of

Option C: Major decrease in the number of

Option D: None of these

Correct Answer: Marginal decrease in the number of ✔

Option A: Sc × Pr

Option B: Pr × St

Option C: Sh × Pr

Option D: St × Sh

Correct Answer: Sc × Pr ✔

Option A: Size

Option B: Durability

Option C: Porosity

Option D: Cost

Correct Answer: Porosity ✔

Option A: Interfacial surface between liquid and gas phase should be large

Option B: Time of contact between the two phases should be less

Option C: Gas velocity should be very low

Option D: Liquid entrainment should be severe

Correct Answer: Interfacial surface between liquid and gas phase should be large ✔

Option A: Liquid stream should be distributed uniformly

Option B: Gas stream should be distributed uniformly

Option C: Both gas as well as liquid streams should be distributed uniformly

Option D: By passing should be completely avoided

Correct Answer: Both gas as well as liquid streams should be distributed uniformly ✔

Option A: 0

Option B: ∞

Option C: -ve

Option D: +ve

Correct Answer: -ve ✔

Option A: Binary mixture is represented by the apex

Option B: Binary mixture is represented by any point inside

Option C: Ternary mixture is represented by the sides

Option D: Pure component is represented by the apex

Correct Answer: Pure component is represented by the apex ✔

Option A: Centrifugal extractor

Option B: Pachuca tanks

Option C: Bollman extractor

Option D: None of these

Correct Answer: Pachuca tanks ✔

Option A: Equal to the heat of formation of surface compound

Option B: Equal to the heat of wetting

Option C: Zero

Option D: Called integral heat of adsorption

Correct Answer: Equal to the heat of wetting ✔

Option A: Molal

Option B: Relative

Option C: Percentage

Option D: None of these

Correct Answer: Molal ✔

Option A: Providing irregular grain size

Option B: Providing minimum percentage of voids

Option C: Having maximum possible points of contact

Option D: None of these

Correct Answer: None of these ✔

Option A: Of slope = 1

Option B: Of slope = 0.1

Option C: Tangential to the equilibrium curve

Option D: None of these

Correct Answer: Tangential to the equilibrium curve ✔

Option A: Selectivity

Option B: Relative volatility

Option C: Solubility

Option D: Density difference

Correct Answer: Relative volatility ✔

Option A: Beginning of falling

Option B: Beginning of constant

Option C: End of falling

Option D: None of these

Correct Answer: Beginning of falling ✔

Option A: √T

Option B: T

Option C: T2

Option D: T3

Correct Answer: T ✔

Option A: Composition

Option B: Temperature

Option C: Total pressure

Option D: All A., B. and C.

Correct Answer: Temperature ✔

Option A: Reflux ratio

Option B: Plate efficiency to be achieved

Option C: Thermal condition of the feed

Option D: Relative volatility

Correct Answer: Thermal condition of the feed ✔

Option A: Dilute solutions, over a small concentration range

Option B: Gaseous solutions at high pressure

Option C: Concentrated solutions

Option D: None of these

Correct Answer: Dilute solutions, over a small concentration range ✔

Option A: M(Xo – XF)

Option B: M(Xo/XF)

Option C: M ln(Xo/XF)

Option D: MXo ln(Xo/XF)

Correct Answer: MXo ln(Xo/XF) ✔

Option A: Multi-component distillation

Option B: Binary distillation

Option C: Gas absorption without chemical reaction

Option D: Gas absorption with chemical reaction

Correct Answer: Gas absorption with chemical reaction ✔

Option A: Use steam distillation

Option B: Use molecular distillation

Option C: Use high pressure distillation

Option D: An azeotrope may be formed during distillation

Correct Answer: An azeotrope may be formed during distillation ✔

Option A: 500

Option B: 1200

Option C: 900

Option D: 800

Correct Answer: 500 ✔

Option A: Continuous

Option B: Steam

Option C: Differential

Option D: Flash

Correct Answer: Differential ✔

Option A: Decreases

Option B: Increases

Option C: Remains unchanged

Option D: None of these

Correct Answer: Decreases ✔

Option A: Means discarding a small fraction of circulating water to prevent and limit the concentration

Option B: Increases the scale forming tendencies of water

Option C: Is undesirable

Option D: All A., B. & C.

Correct Answer: A. Means discarding a small fraction of circulating water to prevent and limit the concentration
of salt and impurities ✔

Option A: Entrainment

Option B: Foaming

Option C: Weeping & dumping

Option D: All A., B. & C.

Correct Answer: D. All A., B. & C. ✔

Option A: 25

Option B: > 25

Option C: < 25

Option D: – 25

Correct Answer: 25 ✔

Option A: Size of component molecules are not equal

Option B: Attractive forces between like and unlike molecules in the solution are approximately equal

Option C: Component molecules are non-polar

Option D: Chemical combination or molecular association between unlike molecules takes place in the

Correct Answer: Component molecules are non-polar ✔

Option A: Sherwood number in mass transfer is analogous to Nusselt number in heat transfer

Option B: Prandtl number in heat transfer is analogous to Schmidt number in mass transfer

Option C: Reynolds number in mass transfer is analogous to Grashoff number in heat transfer

Option D: Reynolds number remains the same in both heat and mass transfer

Correct Answer: Reynolds number in mass transfer is analogous to Grashoff number in heat transfer ✔

Option A: Drift

Option B: Blow down

Option C: Vapor load

Option D: None of these

Correct Answer: Drift ✔

Option A: Extractive

Option B: Azeotropic

Option C: Steam

Option D: Molecular

Correct Answer: Azeotropic ✔

Option A: In solvent extraction, the distribution co-efficient should be as large as possible for solvent

Option B: With increase in pressure, the solubility of gases in solvent increases at a fixed temperature

Option C: Decrease in Murphree plate efficiency is an indication of entrainment in distillation column

Option D: The capacity of a distillation column is maximum at total reflux

Correct Answer: The capacity of a distillation column is maximum at total reflux ✔

Option A: In case of induced draft cooling tower, the fan is placed at the top of the tower

Option B: Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and

Option C: A natural draft cooling tower is recommended to be used, when the air humidity is low and air

Option D: Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb

Correct Answer: D. Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb
temperatur ✔

Option A: The binary diffusivity in liquids is of the order of 10-5 cm2/sec

Option B: Molecular diffusion in solid is much faster than that in liquids

Option C: Particles movement from higher concentration to lower concentration takes place in diffusion

Option D: According to Poiseuille’s law, the permeability decreases with increase in temperature for

Correct Answer: Molecular diffusion in solid is much faster than that in liquids ✔

Option A: Change in barometric pressure does not affect the relative humidity

Option B: In case of a packed tower, the operating velocity is about half of the flooding velocity,

Option C: ‘Elution’ means the desorption of the adsorbed solute by a solvent

Option D: The equilibrium moisture content of the solid can be reduced by increasing the absolute

Correct Answer: D. The equilibrium moisture content of the solid can be reduced by increasing the absolute
humidity ✔

Option A: Mass transfer co-efficient does not account for gas-liquid diffusion

Option B: Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer

Option C: Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process

Option D: Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process

Correct Answer: Mass transfer co-efficient does not account for gas-liquid diffusion ✔

Option A: Mechanical agitation is required, if the system has low interfacial tension

Option B: Sieve tray towers are generally used for systems having low interfacial tension

Option C: When Henry’s law constant is very small, then the mass transfer rate is controlled by the gas

Option D: Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar

Correct Answer: Mechanical agitation is required, if the system has low interfacial tension ✔

Option A: Co-current absorbers are usually used, when the gas to be dissolved in the liquid is a pure

Option B: In case of gas absorption, HETP is equal to HTU, when both the operating line & the

Option C: Hatta number is important in case of gas absorption with chemical reaction

Option D: In actual practice, absorption is an endothermic process, while stripping is an exothermic

Correct Answer: D. In actual practice, absorption is an endothermic process, while stripping is an exothermic
process ✔

Option A: Increases

Option B: Decreases

Option C: Remains unchanged

Option D: Decreases exponentially

Correct Answer: Increases ✔

Option A: D ∝ P0.5

Option B: D ∝ 1/P0.5

Option C: D ∝ 1/P

Option D: D ∝ 1/P1.5

Correct Answer: D ∝ 1/P ✔

Option A: Film

Option B: Penetration

Option C: Surface-renewal

Option D: None of these

Correct Answer: Film ✔

Option A: Classification

Option B: Sedimentation

Option C: Clarification

Option D: Leaching

Correct Answer: Sedimentation ✔

Option A: Yes

Option B: Normally not; but is possible if infinite number of plates are put

Option C: Never

Option D: Yes; if the reflux ratio is maximum

Correct Answer: Never ✔

Option A: Increases

Option B: Decreases

Option C: Remain same

Option D: Either A. or B., depends on the system

Correct Answer: Decreases ✔

Option A: Ethanolamine

Option B: K2CO3

Option C: HCl

Option D: Vacuum gas oil

Correct Answer: Ethanolamine ✔

Option A: Separation of the constituents is the most effective

Option B: No separation will occur

Option C: Amount of solvent required will be minimum

Option D: Solvent flow rate should be very low

Correct Answer: No separation will occur ✔

Option A: Humidity

Option B: Velocity

Option C: Temperature

Option D: All A., B. & C.

Correct Answer: D. All A., B. & C. ✔

Option A: Ponchon-Savarit method

Option B: McCabe-Thiele method

Option C: Enthalpy concentration method

Option D: Tray to tray calculations

Correct Answer: Tray to tray calculations ✔

Option A: Wetted wall column

Option B: Gilliland’s

Option C: Winkelmann’s

Option D: Wike’s

Correct Answer: C. Winkelmann’s ✔

Option A: Cylinder

Option B: Rotary

Option C: Spray

Option D: Fluidised bed

Correct Answer: Cylinder ✔

Option A: Small sizes

Option B: Multi-component distillation

Option C: High pressure operation

Option D: Vacuum distillation

Correct Answer: Small sizes ✔

Option A: Pulsed column

Option B: Sieve plate

Option C: Mixer-settler

Option D: Bollman

Correct Answer: Pulsed column ✔

Option A: Dew point < wet bulb temperature

Option B: Wet bulb temperature < dry bulb temperature

Option C: Both A. and B.

Option D: Neither A. not B.

Correct Answer: C. Both A. and B. ✔

Option A: Liquid side

Option B: Gas side

Option C: Interfacial

Option D: Both liquid and gas side

Correct Answer: Gas side ✔

Option A: Optimum number of trays

Option B: Minimum reboiler size

Option C: Maximum condenser size

Option D: Minimum number of trays

Correct Answer: Maximum condenser size ✔

Option A: Thermal decomposition of bottoms

Option B: Increased relative volatility

Option C: Erosion of the tower

Option D: Very efficient operation

Correct Answer: Thermal decomposition of bottoms ✔

Option A: At ground level

Option B: 2 metres above the ground

Option C: 5 metres above ground

Option D: 10 metres above ground

Correct Answer: At ground level ✔

Option A: Lewis relationship

Option B: Galileo number

Option C: Weber number

Option D: Dean number

Correct Answer: Lewis relationship ✔

Option A: Spray

Option B: Packed

Option C: Bubble cap plate

Option D: Wetted wall

Correct Answer: Wetted wall ✔

Option A: 1

Option B: 0

Option C: ∞

Option D: None of these

Correct Answer: ∞ ✔

Option A: Caustic solution

Option B: Dilute ammoniacal liquor

Option C: Dilute HCl

Option D: Ethanolamine

Correct Answer: Dilute ammoniacal liquor ✔

Option A: Size

Option B: Durability

Option C: Porosity

Option D: Cost

Correct Answer: Porosity ✔

Option A: Packed tower

Option B: Bubble-cap plate column

Option C: Sieve-plate column

Option D: Wetted wall column

Correct Answer: Packed tower ✔

Option A: Diffusion co-efficient

Option B: Mass transfer co-efficient

Option C: NTU

Option D: None of these

Correct Answer: Mass transfer co-efficient ✔

Option A: Schmidt number

Option B: Sherwood number

Option C: Lewis relationship

Option D: Froude number

Correct Answer: Froude number ✔

Option A: Interfacial surface between liquid and gas phase should be large

Option B: Time of contact between the two phases should be less

Option C: Gas velocity should be very low

Option D: Liquid entrainment should be severe

Correct Answer: Interfacial surface between liquid and gas phase should be large ✔

Option A: No change in theoretical

Option B: Marginal decrease in the number of

Option C: Major decrease in the number of

Option D: None of these

Correct Answer: Marginal decrease in the number of ✔

Option A: Sc × Pr

Option B: Pr × St

Option C: Sh × Pr

Option D: St × Sh

Correct Answer: Sc × Pr ✔

Option A: Liquid stream should be distributed uniformly

Option B: Gas stream should be distributed uniformly

Option C: Both gas as well as liquid streams should be distributed uniformly

Option D: By passing should be completely avoided

Correct Answer: Both gas as well as liquid streams should be distributed uniformly ✔

Option A: Molal

Option B: Relative

Option C: Percentage

Option D: None of these

Correct Answer: Molal ✔

Option A: Providing irregular grain size

Option B: Providing minimum percentage of voids

Option C: Having maximum possible points of contact

Option D: None of these

Correct Answer: None of these ✔

Option A: Centrifugal extractor

Option B: Pachuca tanks

Option C: Bollman extractor

Option D: None of these

Correct Answer: Pachuca tanks ✔

Option A: Binary mixture is represented by the apex

Option B: Binary mixture is represented by any point inside

Option C: Ternary mixture is represented by the sides

Option D: Pure component is represented by the apex

Correct Answer: Pure component is represented by the apex ✔

Option A: 0

Option B: ∞

Option C: -ve

Option D: +ve

Correct Answer: -ve ✔

Option A: Of slope = 1

Option B: Of slope = 0.1

Option C: Tangential to the equilibrium curve

Option D: None of these

Correct Answer: Tangential to the equilibrium curve ✔

Option A: Selectivity

Option B: Relative volatility

Option C: Solubility

Option D: Density difference

Correct Answer: Relative volatility ✔

Option A: Beginning of falling

Option B: Beginning of constant

Option C: End of falling

Option D: None of these

Correct Answer: Beginning of falling ✔

Option A: Equal to the heat of formation of surface compound

Option B: Equal to the heat of wetting

Option C: Zero

Option D: Called integral heat of adsorption

Correct Answer: Equal to the heat of wetting ✔

Option A: M(Xo – XF)

Option B: M(Xo/XF)

Option C: M ln(Xo/XF)

Option D: MXo ln(Xo/XF)

Correct Answer: MXo ln(Xo/XF) ✔

Option A: √T

Option B: T

Option C: T2

Option D: T3

Correct Answer: T ✔

Option A: Composition

Option B: Temperature

Option C: Total pressure

Option D: All A, B. and C.

Correct Answer: Temperature ✔

Option A: Multi-component distillation

Option B: Binary distillation

Option C: Gas absorption without chemical reaction

Option D: Gas absorption with chemical reaction

Correct Answer: Gas absorption with chemical reaction ✔

Option A: Dilute solutions, over a small concentration range

Option B: Gaseous solutions at high pressure

Option C: Concentrated solutions

Option D: None of these

Correct Answer: Dilute solutions, over a small concentration range ✔

Option A: Reflux ratio

Option B: Plate efficiency to be achieved

Option C: Thermal condition of the feed

Option D: Relative volatility

Correct Answer: Thermal condition of the feed ✔

Option A: Use steam distillation

Option B: Use molecular distillation

Option C: Use high pressure distillation

Option D: An azeotrope may be formed during distillation

Correct Answer: An azeotrope may be formed during distillation ✔

Option A: 500

Option B: 1200

Option C: 900

Option D: 800

Correct Answer: 500 ✔

Option A: Entrainment

Option B: Foaming

Option C: Weeping & dumping

Option D: All A., B. & C.

Correct Answer: D. All A., B. & C. ✔

Option A: Decreases

Option B: Increases

Option C: Remains unchanged

Option D: None of these

Correct Answer: Decreases ✔

Option A: 25

Option B: > 25

Option C: < 25

Option D: – 25

Correct Answer: 25 ✔

Option A: Size of component molecules are not equal

Option B: Attractive forces between like and unlike molecules in the solution are approximately equal

Option C: Component molecules are non-polar

Option D: Chemical combination or molecular association between unlike molecules takes place in the

Correct Answer: Component molecules are non-polar ✔

Option A: Reducing the axial mixing

Option B: Increasing the rate of extraction

Option C: Maintaining the concentration difference between the two phases

Option D: All A , B & C.

Correct Answer: All A , B & C. ✔

Option A: Continuous

Option B: Steam

Option C: Differential

Option D: Flash

Correct Answer: Differential ✔

Option A: Means discarding a small fraction of circulating water to prevent and limit the concentration

Option B: Increases the scale forming tendencies of water

Option C: Is undesirable

Option D: All A., B. & C.

Correct Answer: A. Means discarding a small fraction of circulating water to prevent and limit the concentration
of salt and impurities ✔

Option A: Sherwood number in mass transfer is analogous to Nusselt number in heat transfer

Option B: Prandtl number in heat transfer is analogous to Schmidt number in mass transfer

Option C: Reynolds number in mass transfer is analogous to Grashoff number in heat transfer

Option D: Reynolds number remains the same in both heat and mass transfer

Correct Answer: Reynolds number in mass transfer is analogous to Grashoff number in heat transfer ✔

Option A: Drift

Option B: Blow down

Option C: Vapor load

Option D: None of these

Correct Answer: Drift ✔

Option A: Extractive

Option B: Azeotropic

Option C: Steam

Option D: Molecular

Correct Answer: Azeotropic ✔