Mass Transfer MCQs

Option A: The mole fraction of solute is directly proportional to the molality of a ‘dilute’ solution

Option B: For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both

Option C: Azeotropes obey Raoult’s law at all temperature

Option D: The relative volatility of a binary mixture at the Azeotropic composition is 1

Correct Answer: C. Azeotropes obey Raoult’s law at all temperature ✔

Option A: Dew point

Option B: Bubble point

Option C: Dry bulb temperature

Option D: Wet bulb temperature

Correct Answer: Dew point ✔

Option A: Increased efficiency

Option B: Decreased efficiency

Option C: High operating cost

Option D: Better gas liquid contact

Correct Answer: High operating cost ✔

Option A: 10-9 cm/sec

Option B: 10-1 cm2/sec

Option C: 10-3 sec/cm

Option D: 10-4 cm2/sec2

Correct Answer: 10-1 cm2/sec ✔

Option A: Increases

Option B: Decreases

Option C: Does not affect

Option D: Exponentially increases

Correct Answer: Decreases ✔

Option A: Tray

Option B: Tunnel

Option C: Conveyor

Option D: Festoon

Correct Answer: Tunnel ✔

Option A: Raschig

Option B: Lessing

Option C: Cross-partition

Option D: Single spiral

Correct Answer: Raschig ✔

Option A: rpm

Option B: Inclination with ground surface

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: Alkalis

Option B: SO2

Option C: H2SO4

Option D: Oxidising atmosphere

Correct Answer: Oxidising atmosphere ✔

Option A: 1-5

Option B: 10-60

Option C: 200-300

Option D: > 500

Correct Answer: 10-60 ✔

Option A: L/G

Option B: G/L

Option C: Always < 1

Option D: None of these

Correct Answer: L/G ✔

Option A: Schmidt

Option B: Sherwood

Option C: Peclet

Option D: Stanton

Correct Answer: Schmidt ✔

Option A: An irreversible phenomenon

Option B: A reversible phenomenon

Option C: Accompanied by evolution of heat

Option D: Both B. and C.

Correct Answer: D. Both B. and C. ✔

Option A: Absorption

Option B: Adsorption

Option C: Extraction

Option D: Leaching

Correct Answer: Adsorption ✔

Option A: Large latent heat

Option B: Low viscosity

Option C: Small latent heat

Option D: None of these

Correct Answer: Large latent heat ✔

Option A: Separation becomes more efficient

Option B: Number of plates increases

Option C: Column diameter increases

Option D: None of these

Correct Answer: Number of plates increases ✔

Option A: Increases

Option B: Remains unchanged

Option C: Decreases

Option D: Decreases linearly

Correct Answer: Increases ✔

Option A: Latent heat

Option B: Humid heat

Option C: Specific heat

Option D: Sensible heat

Correct Answer: Specific heat ✔

Option A: Adsorption

Option B: Binary distillation

Option C: Gas absorption

Option D: Humidification

Correct Answer: Humidification ✔

Option A: No reflux

Option B: Total reflux

Option C: Zero reflux ratio

Option D: Minimum reflux ratio

Correct Answer: Total reflux ✔

Option A: √T

Option B: T

Option C: T1.5

Option D: T3

Correct Answer: T ✔

Option A: Tray

Option B: Rotary

Option C: Fluidised bed

Option D: None of these

Correct Answer: Tray ✔

Option A: Dry those materials which have very high unbound moisture content

Option B: Reduce drying temperature

Option C: Increase drying temperature

Option D: Dry materials having high bound moisture content

Correct Answer: Reduce drying temperature ✔

Option A: Pr = Sc; percentage change in heat and mass transfer flux will be the same for a given change

Option B: Pr = Sc = 1; total mass, momentum and thermal diffusivity will be the same

Option C: Both A. and B.

Option D: Pr = Sc; there won’t be any change in heat and mass transfer flux with changes in degree of

Correct Answer: C. Both A. and B. ✔

Option A: 0.0

Option B: 0.2

Option C: 0.4

Option D: 1.0

Correct Answer: 0.4 ✔

Option A: Increases

Option B: Decreases

Option C: Remains unchanged

Option D: Depends on the pressure of the system

Correct Answer: Decreases ✔

Option A: Vapour is in equilibrium with the liquid at the gas temperature

Option B: Vapour is in equilibrium with the liquid at the room temperature

Option C: Partial pressure of vapour equals the vapour pressure of the liquid at room temperature

Option D: None of these

Correct Answer: Vapour is in equilibrium with the liquid at the gas temperature ✔

Option A: Specific humidity

Option B: Partial pressure of vapour

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: Bubble the gas through liquid

Option B: Spray the liquid on gas stream

Option C: Either A. or B. would suffice

Option D: None of these

Correct Answer: Bubble the gas through liquid ✔

Option A: Parallel

Option B: Straight

Option C: Both parallel and straight

Option D: Neither parallel nor straight

Correct Answer: Both parallel and straight ✔

Option A: Viscosity with concentration

Option B: Degree of ideality of the solution

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: Pressure

Option B: Temperature

Option C: Nature of the components

Option D: None of these

Correct Answer: None of these ✔

Option A: Molecular velocity only

Option B: Pore radius of the catalyst only

Option C: Molecular mean free path only

Option D: Molecular velocity and pore radius of the catalyst

Correct Answer: Molecular velocity and pore radius of the catalyst ✔

Option A: The ratio of number of ideal plates to actual plates

Option B: The ratio of number of actual plates to ideal plates

Option C: Same as the Murphree efficiency

Option D: Always more than the point efficiency

Correct Answer: The ratio of number of ideal plates to actual plates ✔

Option A: Low reflux ratio

Option B: Less number of trays

Option C: Small cross-section column

Option D: High reflux ratio

Correct Answer: High reflux ratio ✔

Option A: Above which it will always become damp

Option B: Below which it will always stay dry

Option C: Both A. and B.

Option D: Above Which it will always become dry and below which it will always stay damp

Correct Answer: C. Both A. and B. ✔

Option A: Hot cupric oxide

Option B: Heated charcoal

Option C: Cold Ca(OH)2

Option D: Alumina

Correct Answer: Heated charcoal ✔

Option A: Natural draft cooling tower

Option B: Induced draft cooling tower

Option C: Spray chamber

Option D: None of these

Correct Answer: Spray chamber ✔

Option A: Changes the relative volatility of the original components

Option B: Should be of high volatility

Option C: Should form azeotropes with the original components

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

Correct Answer: Changes the relative volatility of the original components ✔

Option A: Less

Option B: More

Option C: Same

Option D: Unpredictable

Correct Answer: Less ✔

Option A: Relative humidity

Option B: Partial pressure of vapour

Option C: Wet bulb temperature

Option D: None of these

Correct Answer: Wet bulb temperature ✔

Option A: Escaping tendency of each component from the liquid phase to the vapor phase is exactly

Option B: Temperature of the liquid phase is equal to that of the vapor phase

Option C: Total pressure throughout the liquid phase is equal to that throughout the vapor phase

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

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

Option A: Increases with increase in

Option B: Is one at unity value of

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: a1 = a2

Option B: a1 = 2a2

Option C: a1 = 0.5 a2

Option D: None of these

Correct Answer: None of these ✔

Option A: Always smaller than

Option B: Always greater than

Option C: Not related to

Option D: None of these

Correct Answer: Always smaller than ✔

Option A: Liquid phase resistance-controlled

Option B: Gas phase resistance controlled

Option C: Impossible

Option D: Driven by a non-linear driving force

Correct Answer: Gas phase resistance controlled ✔

Option A: Atmospheric

Option B: Vacuum

Option C: High pressure

Option D: None of these

Correct Answer: Vacuum ✔

Option A: Natural

Option B: Forced

Option C: Induced

Option D: None of these

Correct Answer: Natural ✔

Option A: Temperature and pressure

Option B: Concentration

Option C: Nature of the constituents

Option D: None of these

Correct Answer: None of these ✔

Option A: Hot water

Option B: Hexane

Option C: Dilute H2SO4

Option D: Lime water

Correct Answer: Hot water ✔

Option A: Flow rate of liquid

Option B: Flow rate of gas

Option C: Type and size of packing

Option D: None of these

Correct Answer: None of these ✔

Option A: Dry bulb temperature

Option B: Dew point

Option C: Wet bulb temperature

Option D: None of these

Correct Answer: Wet bulb temperature ✔

Option A: Heat gain or loss

Option B: Flow rate of entering liquid

Option C: Flow rate of gas

Option D: None of these

Correct Answer: Flow rate of entering liquid ✔

Option A: Equilibrium

Option B: Critical

Option C: Unbound

Option D: Bound

Correct Answer: Unbound ✔

Option A: Added to alter the relative volatility of the mixture

Option B: Of high volatility

Option C: Present in overhead stream

Option D: Of high viscosity to give high tray efficiency

Correct Answer: Added to alter the relative volatility of the mixture ✔

Option A: Partial pressure of vapour in the mixture

Option B: Heat capacity of the vapour

Option C: Density of the vapour

Option D: None of these

Correct Answer: Partial pressure of vapour in the mixture ✔

Option A: 1

Option B: 0.5

Option C: 10

Option D: 0

Correct Answer: 1 ✔

Option A: D ∝ T

Option B: D ∝ T0.5

Option C: D ∝ T1.5

Option D: D ∝ T2

Correct Answer: D ∝ T ✔

Option A: Integral heat of adsorption

Option B: Heat of wetting

Option C: Differential heat of adsorption

Option D: Heat of normal condensation

Correct Answer: Integral heat of adsorption ✔

Option A: Binary

Option B: Ternary

Option C: Constant boiling point

Option D: None of these

Correct Answer: Constant boiling point ✔

Option A: Highest temperatures is near the feed plate

Option B: Driving force for the liquid flow is its weight

Option C: Vapors are not always at their dew points

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

Correct Answer: Driving force for the liquid flow is its weight ✔

Option A: Reboiler load

Option B: Number of plates

Option C: Condenser load

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

Correct Answer: Number of plates ✔

Option A: Pressure

Option B: Humidity

Option C: Temperature

Option D: Both B. and C.

Correct Answer: D. Both B. and C. ✔

Option A: Dew point

Option B: Wet bulb

Option C: Both A & B

Option D: Neither A nor B

Correct Answer: Both A & B ✔

Option A: Driving force for the vapour flow is the pressure drop

Option B: Liquids are not always at their bubble points

Option C: Pressure increases gradually from bottom to the top of the column

Option D: None of these

Correct Answer: Driving force for the vapour flow is the pressure drop ✔

Option A: 21.7

Option B: 20

Option C: 27.3

Option D: 18.7

Correct Answer: 18.7 ✔

Option A: Same as “Van der Waals” adsorption

Option B: Characterised by adsorption of heat

Option C: An irreversible phenomenon

Option D: A reversible phenomenon

Correct Answer: An irreversible phenomenon ✔

Option A: L/mG

Option B: G/mL

Option C: mL/G

Option D: LG/m

Correct Answer: L/mG ✔

Option A: Zero

Option B: Unity

Option C: Infinity

Option D: None of these

Correct Answer: Infinity ✔

Option A: Constant molal overflow

Option B: Total reflux

Option C: Constant relative volatility

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

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

Option A: Is of low volatility

Option B: Forms a low boiling azeotrope

Option C: Forms a high boiling azeotrope

Option D: Does not alter the relative volatility of the original components

Correct Answer: Forms a low boiling azeotrope ✔

Option A: Slope of the operating line in stripping section decreases

Option B: Number of plates decreases very slowly first and then more and more rapidly

Option C: Total cost first decreases and then increases

Option D: Liquid flow increases while the vapor flow decreases for a system

Correct Answer: Total cost first decreases and then increases ✔

Option A: Evaporation

Option B: Blowdown

Option C: Entrainment

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

Correct Answer: D. All A., B. & C. ✔

Option A: Have low weight per unit volume

Option B: Have large surface area per unit volume

Option C: Have large free cross-section

Option D: Hold up large amount of liquid in the packing

Correct Answer: Hold up large amount of liquid in the packing ✔

Option A: Greater than that computed for ideality

Option B: Less than that computed for ideality

Option C: Less than the sum of the vapour pressure of the components

Option D: None of these

Correct Answer: Greater than that computed for ideality ✔

Option A: Stanton number

Option B: Peclet number

Option C: Thermal diffusivity

Option D: Momentum diffusivity

Correct Answer: Stanton number ✔

Option A: Mole fractions

Option B: Mole ratios

Option C: Partial pressure

Option D: Mass fractions

Correct Answer: Partial pressure ✔

Option A: The product composition but not the fraction vaporised

Option B: The product composition as well as the fraction vaporised

Option C: The fraction vaporised but not the product composition

Option D: Neither the product composition nor the fraction vaporised

Correct Answer: The fraction vaporised but not the product composition ✔

Option A: Phase change of the solute as it dissolves in the solvent

Option B: Diffusion of the solute through the solvent in the pores to the outside of the particle

Option C: Diffusion of the solute from the solution in contact with the particle to the main bulk of the

Option D: All A , B. & C.

Correct Answer: D. All A , B. & C. ✔

Option A: Degree of dispersion of one fluid in the other

Option B: Interfacial surface exposed between the phases

Option C: Both A. & B.

Option D: None of these

Correct Answer: None of these ✔

Option A: Pressure

Option B: Temperature

Option C: Both A. & B.

Option D: Neither A. nor B.

Correct Answer: Temperature ✔

Option A: Temperature is less

Option B: Total pressure is less

Option C: Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium

Option D: Saturated steam is used for steam distillation

Correct Answer: C. Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium
condition ✔

Option A: Dry bulb

Option B: Wet bulb

Option C: Dew point

Option D: None of these

Correct Answer: Wet bulb ✔

Option A: Means the amount of heat thrown away (KCal/hr.) by the cooling tower

Option B: Is equal to the number of kg, of water circulated times the cooling range

Option C: Both A. & B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. & B. ✔

Option A: Viscosity

Option B: Vapor pressure

Option C: Freezing point

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

Correct Answer: D. All A., B. & C. ✔

Option A: Increases with temperature rise

Option B: Decreases with temperature rise

Option C: Decreases with decrease in pressure

Option D: Increases with increase in pressure

Correct Answer: Decreases with decrease in pressure ✔

Option A: Rectification

Option B: Absorption

Option C: Ion-exchange

Option D: Adsorption

Correct Answer: Ion-exchange ✔

Option A: Unsaturated surface

Option B: Constant rate

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: Temperature

Option B: Viscosity of solvent

Option C: Pressure

Option D: Size of the solid

Correct Answer: Temperature ✔

Option A: Cold water leaving the tower and the wet bulb temperature of the surrounding air

Option B: Hot water entering the tower and the wet bulb temperature of the surrounding air

Option C: Hot water entering the tower and the cooled water leaving the tower

Option D: None of these

Correct Answer: Hot water entering the tower and the cooled water leaving the tower ✔

Option A: Murphree efficiency > point efficiency

Option B: Murphree efficiency < point efficiency

Option C: Murphree efficiency = point efficiency

Option D: Murphree efficiency ≠ point efficiency

Correct Answer: Murphree efficiency = point efficiency ✔

Option A: Density

Option B: Molal concentration

Option C: Kinematic viscosity

Option D: Velocity head

Correct Answer: Kinematic viscosity ✔

Option A: Degree of ideality

Option B: Viscosity

Option C: Both A & B

Option D: Neither A nor B

Correct Answer: Both A & B ✔

Option A: Number of plates is zero

Option B: Number of plates is infinity

Option C: Minimum number of the theoretical plates is required

Option D: Separation is most efficient

Correct Answer: Number of plates is infinity ✔

Option A: Gas

Option B: Liquid

Option C: Both A. & B.

Option D: Neither A. nor B.

Correct Answer: Liquid ✔

A. Mixer-settler extractor
B. Centrifugal extractor
C. Pulsed extractor
D. Packed extraction tower

Correct Answer: B. Centrifugal extractor
C ✔

Option A: Zero

Option B: Infinity

Option C: Unity

Option D: Data insufficient

Correct Answer: Infinity ✔

Option A: P

Option B: 1/P

Option C: 1/√P

Option D: √P

Correct Answer: P ✔

Option A: Decreases

Option B: Increases

Option C: Depends on the extent of heating

Option D: Remain unchanged

Correct Answer: Increases ✔

Option A: A pure component

Option B: A binary mixture

Option C: A ternary mixture

Option D: Partially miscible ternary system

Correct Answer: A binary mixture ✔