Mass Transfer MCQs

Option A: Avoiding deposition on cooler surfaces

Option B: Formation of nuclei

Option C: Crystal growth

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

Correct Answer: D. All A., B. and C. ✔

Option A: Mass diffusivity to momentum diffusivity

Option B: Thermal diffusivity to mass diffusivity

Option C: Momentum diffusivity to thermal diffusivity

Option D: None of these

Correct Answer: Thermal diffusivity to mass diffusivity ✔

Option A: Sherwood

Option B: Schmidt

Option C: Peclet

Option D: Stanton

Correct Answer: Sherwood ✔

Option A: Distillation column

Option B: Evaporator

Option C: Dryer

Option D: Crystalliser

Correct Answer: Distillation column ✔

Option A: T3/2 and T

Option B: T and T3/2

Option C: √T and T3/2

Option D: T3/2 and √T

Correct Answer: T3/2 and T ✔

Option A: At ambient temperature

Option B: At its boiling point

Option C: In its vapor form

Option D: None of these

Correct Answer: At its boiling point ✔

Option A: Pressure

Option B: Thermal

Option C: Concentration

Option D: Forced

Correct Answer: Concentration ✔

Option A: Wetted wall

Option B: Bubble cap

Option C: Perforated tray

Option D: Packed

Correct Answer: Wetted wall ✔

Option A: Selectivity

Option B: Distribution co-efficient

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: D. Neither A. nor B. ✔

Option A: Wetted wall towers

Option B: Packed towers

Option C: Venturi scrubbers

Option D: Agitated vessels

Correct Answer: Agitated vessels ✔

Option A: Mass transfer co-efficient

Option B: Thermal diffusivity

Option C: Kinematic viscosity

Option D: Volumetric diffusivity

Correct Answer: Mass transfer co-efficient ✔

Option A: < 1 and ≈ 1

Option B: 1 and 0

Option C: > 1 and ≈ 1

Option D: 0 and ≈ 1

Correct Answer: < 1 and ≈ 1 ✔

Option A: Increase in rate of drying

Option B: Increasing temperatures both on the surface and within the solid

Option C: Decreasing temperatures

Option D: None of these

Correct Answer: Increasing temperatures both on the surface and within the solid ✔

Option A: Increasing temperature

Option B: Decreasing pressure

Option C: Increasing pressure

Option D: No means

Correct Answer: Decreasing pressure ✔

Option A: The entire amount of C is transferred to solvent B

Option B: Less than 2 kg but more than 1 kg of C is transferred to solvent B

Option C: Less than 1 kg of C is transferred to B

Option D: No amount of C is transferred to B

Correct Answer: The entire amount of C is transferred to solvent B ✔

Option A: 4

Option B: 8

Option C: 9

Option D: 10

Correct Answer: 9 ✔

Option A: Rotary

Option B: Fluidised bed

Option C: Vacuum

Option D: Spray

Correct Answer: Fluidised bed ✔

Option A: Unidirectional diffusion from liquid to gas phase

Option B: Unidirectional diffusion from gas to liquid phase

Option C: Either A. or B.

Option D: A counter diffusion at an almost equal molar rate

Correct Answer: A counter diffusion at an almost equal molar rate ✔

Option A: Silica gel

Option B: Alumina

Option C: Fuller’s earth

Option D: Activated carbon

Correct Answer: Activated carbon ✔

Option A: Toor and Marcello

Option B: Fick

Option C: Danckwerts

Option D: Stefan

Correct Answer: Danckwerts ✔

Option A: 1.2 to 1.5

Option B: 2.5 to 3

Option C: 3 to 4

Option D: 5

Correct Answer: 1.2 to 1.5 ✔

Option A: Sherwood

Option B: Stanton

Option C: Lewis

Option D: Peclet

Correct Answer: Lewis ✔

Option A: 1

Option B: 1 to 5

Option C: 5 to 10

Option D: > 10

Correct Answer: 1 ✔

Option A: The water entrained by the circulating air

Option B: Dependent on the water lost by evaporation

Option C: Desirable

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

Correct Answer: The water entrained by the circulating air ✔

Option A: Lies below the equilibrium line

Option B: Lies above the equilibrium line

Option C: And equilibrium lines are parallel

Option D: Is far from the equilibrium line

Correct Answer: And equilibrium lines are parallel ✔

Option A: Increases

Option B: Decreases

Option C: Remains unchanged

Option D: Increases exponentially

Correct Answer: Decreases ✔

Option A: Anthracite coal

Option B: Rag paper

Option C: Bamboo

Option D: Inorganic solids

Correct Answer: Bamboo ✔

Option A: Humidified with wet bulb temperature decreasing

Option B: Humidified at constant wet bulb temperature

Option C: Dehumidified

Option D: None of these

Correct Answer: Humidified with wet bulb temperature decreasing ✔

Option A: Molecular

Option B: Extractive

Option C: Steam

Option D: Simple

Correct Answer: Simple ✔

Option A: Vapour laden gas at 1 atm. and room temperature

Option B: Gas plus its accompanying vapour at 1 atm. and room temperature

Option C: Gas plus its accompanying vapour at 1 atm. and gas temperature

Option D: Vapour laden gas at 1 atm. and gas temperature

Correct Answer: Gas plus its accompanying vapour at 1 atm. and gas temperature ✔

Option A: Vetrocoke solution

Option B: Monoethanolamine (MEA)

Option C: Dilute

Option D: Hot water

Correct Answer: Monoethanolamine (MEA) ✔

Option A: Varies inversely as the pressure

Option B: Varies directly as the pressure

Option C: Is independent of pressure

Option D: Is equal to the volumetric diffusivity

Correct Answer: Is independent of pressure ✔

Option A: cm2/sec gm . mole

Option B: gm moles/cm2 . sec

Option C: gm moles/cm. sec

Option D: gm moles/cm2. sec

Correct Answer: gm moles/cm. sec ✔

Option A: Freeze

Option B: Spray

Option C: Tray

Option D: Rotary

Correct Answer: Spray ✔

Option A: Danckwerts

Option B: Toor and Marcello

Option C: Higbie

Option D: Kissinevskii

Correct Answer: Higbie ✔

Option A: Concentrated solution and non-isothermal operation

Option B: Dilute solution and non-isothermal operation

Option C: Dilute solution and isothermal operation

Option D: Concentrated solution and isothermal operation

Correct Answer: Dilute solution and isothermal operation ✔

Option A: 0.048

Option B: 0.079

Option C: 0.122

Option D: 0.152

Correct Answer: 0.152 ✔

Option A: Drying cost per unit weight of dried product is less

Option B: Product with more uniform moisture content is produced

Option C: Equipment size required is smaller

Option D: All A , B. & C.

Correct Answer: D. All A , B. & C. ✔

Option A: Nature of the vapor

Option B: Temperature of the mixture

Option C: Composition of the mixture

Option D: None of these

Correct Answer: None of these ✔

Option A: T

Option B: √T

Option C: T2

Option D: 1/T

Correct Answer: T ✔

Option A: Fixed bed absorption

Option B: Moving bed absorption

Option C: Fixed bed adsorption

Option D: Moving bed adsorption

Correct Answer: Moving bed adsorption ✔

Option A: Unbound

Option B: Free

Option C: Critical

Option D: Bound

Correct Answer: Free ✔

Option A: Molecular

Option B: Azeotropic

Option C: Extractive

Option D: Flash

Correct Answer: Extractive ✔

Option A: 0.31

Option B: 0.107

Option C: 0.017

Option D: 0.215

Correct Answer: 0.215 ✔

Option A: 100

Option B: > 100

Option C: < 100

Option D: None of these

Correct Answer: 100 ✔

Option A: Uses molal units for material and energy balance

Option B: Uses weight fractions to express liquid and vapour composition

Option C: Can use any type of units

Option D: Is more accurate than Ponchon-Savarit method

Correct Answer: Uses molal units for material and energy balance ✔

Option A: Heat and mass

Option B: Mass and momentum

Option C: Heat and momentum

Option D: Heat, momentum and mass

Correct Answer: Heat and mass ✔

Option A: Decreases with decrease in pressure

Option B: At constant humidity & total pressure is fixed

Option C: Corresponding to any point on the humidity chart is obtained by projecting a line through this

Option D: All A , B. & C.

Correct Answer: D. All A , B. & C. ✔

Option A: 1

Option B: 0.24

Option C: 3.97

Option D: 600

Correct Answer: 1 ✔

Option A: And humidified

Option B: And dehumidified with increase in wet bulb temperature

Option C: At the same relative humidity

Option D: And dehumidified with decrease in wet bulb temperature

Correct Answer: And dehumidified with decrease in wet bulb temperature ✔

Option A: More

Option B: Less

Option C: Same

Option D: Either more or less; depends on the system

Correct Answer: Same ✔

Option A: Less than

Option B: More than

Option C: Equal to

Option D: None of these

Correct Answer: More than ✔

Option A: Moles transferred/ [(time) (area) (mole fraction)]

Option B: Moles transferred/ [(time) (area) (mass A/mass B)]

Option C: Moles transferred/ [(time) (area) (pressure)]

Option D: None of these

Correct Answer: None of these ✔

Option A: 1

Option B: ∞

Option C: 0.5

Option D: 2

Correct Answer: ∞ ✔

Option A: High pressure

Option B: Low pressure

Option C: Extractive

Option D: Steam

Correct Answer: Steam ✔

Option A: Increases tray efficiency

Option B: Decreases tray efficiency

Option C: Reduces pressure drop

Option D: Is desirable, as it provides improved vapour-liquid contact

Correct Answer: Decreases tray efficiency ✔

Option A: Cracks develop on the surface of the solid

Option B: Rate of drying decreases abruptly

Option C: Surface evaporation of unbound moisture occurs

Option D: None of these

Correct Answer: Surface evaporation of unbound moisture occurs ✔

Option A: 0 to 0.5

Option B: 0 to 3

Option C: 1.25 to 2

Option D: 5 to 15

Correct Answer: 1.25 to 2 ✔

Option A: Isothermal operation

Option B: Dilute solutions

Option C: Dilute solutions and isothermal operation

Option D: None of these

Correct Answer: Dilute solutions ✔

Option A: Is a static bed leaching equipment

Option B: Is used for extraction of oil from oilseed

Option C: Is a centrifugal extractor

Option D: Employs only counter-current extraction

Correct Answer: Is used for extraction of oil from oilseed ✔

Option A: Solvent of low latent heat of vaporisation should be used

Option B: Solvent of low freezing point should be used

Option C: Large quantity of solvent is required to extract the solute

Option D: Very small quantity of solvent is required

Correct Answer: Large quantity of solvent is required to extract the solute ✔

Option A: Liquid-liquid extraction

Option B: Leaching

Option C: Absorption

Option D: None of these

Correct Answer: Leaching ✔

Option A: Pulse column

Option B: Spray column

Option C: Mixer settler

Option D: Baffle tower

Correct Answer: Pulse column ✔

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: 0

Option B: 1

Option C: 2

Option D: 3

Correct Answer: 3 ✔

Option A: Evaporation

Option B: Drying

Option C: Crystallisation

Option D: Both B. and C.

Correct Answer: D. Both B. and C. ✔

Option A: Thermal diffusivity/mass diffusivity

Option B: Thermal diffusivity/momentum diffusivity

Option C: Momentum diffusivity/mass diffusivity

Option D: Mass diffusivity/thermal diffusivity

Correct Answer: Momentum diffusivity/mass diffusivity ✔

Option A: Operating

Option B: Total

Option C: Minimum

Option D: Maximum permissible

Correct Answer: Total ✔

Option A: Lower than

Option B: Higher than

Option C: Equal to

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

Correct Answer: Lower than ✔

Option A: Form minimum boiling azeotrope

Option B: Have very wide boiling points

Option C: Have very close boiling points

Option D: Form constant boiling azeotrope

Correct Answer: Have very wide boiling points ✔

Option A: Distillation

Option B: Solvent extraction

Option C: Absorption

Option D: None of these

Correct Answer: Solvent extraction ✔

Option A: Comprises of thin bed of substances of extended surface having high porosity

Option B: Helps in increasing the bubble size entering the settler

Option C: Helps in increasing the settling rate of the bubbles

Option D: All ‘a’, ‘b’, & ‘c’

Correct Answer: D. All ‘a’, ‘b’, & ‘c’ ✔

Option A: Decreases with time

Option B: Increases with time

Option C: Does not change with time

Option D: Does not affect the moisture content of the wet solid

Correct Answer: Does not change with time ✔

Option A: Increases

Option B: Decreases

Option C: Remains unaffected

Option D: And the heat required in reboiler decreases

Correct Answer: Increases ✔

Option A: Increase

Option B: Decrease

Option C: Remain same

Option D: Depend on saturated boiling point; may increase or decrease

Correct Answer: Increase ✔

Option A: Suction pump

Option B: Compressed air jet

Option C: Steam jet ejector with a barometric condenser

Option D: None of these

Correct Answer: Steam jet ejector with a barometric condenser ✔

Option A: Fick’s law

Option B: Gibb’s equation

Option C: Freundlich equation

Option D: None of these

Correct Answer: Freundlich equation ✔

Option A: Extractive distillation

Option B: Crystallisation

Option C: Absorption

Option D: None of these

Correct Answer: Crystallisation ✔

Option A: Zero

Option B: Hundred

Option C: Both zero and hundred

Option D: None of these

Correct Answer: Both zero and hundred ✔

Option A: Increase

Option B: Decrease

Option C: Remain unchanged

Option D: Increase/decrease; depends on the temperature

Correct Answer: Increase ✔

Option A: Psychrometric ratio

Option B: Lewis number

Option C: Sherwood number

Option D: Stanton number

Correct Answer: Lewis number ✔

Option A: Momentum diffusivity to the mass diffusivity

Option B: Thermal diffusivity to the mass diffusivity

Option C: Momentum diffusivity to the thermal diffusivity

Option D: None of these

Correct Answer: Momentum diffusivity to the mass diffusivity ✔

Option A: Less number of trays are required

Option B: Composition of the residue remains unchanged

Option C: More number of trays are required but the residue composition remains unchanged

Option D: More number of trays are required and the residue composition is more dilute in methanol

Correct Answer: Less number of trays are required ✔

Option A: Liquid is stripped of high boiler

Option B: Liquid is enriched with high boiler

Option C: Vapour is stripped of low boiler

Option D: None of these

Correct Answer: Liquid is enriched with high boiler ✔

Option A: Long tube

Option B: Short tube

Option C: Vacuum

Option D: Falling film

Correct Answer: Long tube ✔

Option A: Film

Option B: Surface renewal

Option C: Penetration

Option D: None of these

Correct Answer: Surface renewal ✔

Option A: The pressure drop and hence the pumping cost will be very high

Option B: It cannot be recovered by distillation

Option C: Its recovery cost by distillation may be prohibitively high

Option D: It will decompose while recovering by distillation

Correct Answer: Its recovery cost by distillation may be prohibitively high ✔

Option A: Increased capacity of the absorber

Option B: Increase in equilibrium solubility

Option C: Decrease in equilibrium solubility

Option D: None of these

Correct Answer: Decrease in equilibrium solubility ✔

Option A: Mass transfer is accompanied by reaction

Option B: Diffusion of A is in stagnant medium B

Option C: Molecular mean free path is high

Option D: There is equimolar counter diffusion

Correct Answer: There is equimolar counter diffusion ✔

Option A: Increases

Option B: Decreases

Option C: Remain unaffected

Option D: Increases Linearly

Correct Answer: Increases ✔

Option A: Inversely

Option B: Linearly

Option C: Exponentially

Option D: None of these

Correct Answer: Linearly ✔

Option A: Increase in Murphree plate efficiency

Option B: Decrease in pressure drop

Option C: Decrease in liquid hold up in the column

Option D: Increase in pressure drop

Correct Answer: Increase in pressure drop ✔

Option A: Dissolving gold from ores

Option B: Dissolving pharmaceutical products from bark or roots

Option C: Dissolving sugar from the cells of the beet

Option D: Removing nicotine from its water solution by kerosene

Correct Answer: Removing nicotine from its water solution by kerosene ✔

Option A: 1

Option B: 0.5

Option C: 2

Option D: 8

Correct Answer: 1 ✔

Option A: Increases

Option B: Decreases

Option C: Remain same

Option D: May increase or decrease; depends on individual design

Correct Answer: Increases ✔

Option A: Calculated

Option B: Unknown

Option C: Known

Option D: Not required

Correct Answer: Known ✔

Option A: Penetration

Option B: Surface renewal

Option C: Film

Option D: None of these

Correct Answer: Penetration ✔

Option A: Grid tray tower

Option B: Perforated tray tower

Option C: Wetted wall tower

Option D: Bubble cap tower

Correct Answer: Bubble cap tower ✔

Option A: 25%

Option B: 50%

Option C: 70%

Option D: 90%

Correct Answer: 50% ✔

Option A: D

Option B: D2

Option C: D0.5

Option D: 1/D

Correct Answer: D ✔