Mass Transfer MCQs

Question 1

Air at a particular humidity is heated in a furnace. The new dew point

Accepted Answer

Increases

Answer

Decreases

Answer

Depends on the extent of heating

Answer

Remain unchanged

Question 2

In stripping section of continuous distillation column, the

Accepted Answer

Liquid is enriched with high boiler

Answer

Liquid is stripped of high boiler

Answer

Vapour is stripped of low boiler

Answer

None of these

Question 3

Diffusivity in concentrated solutions differs from that in dilute solutions, because of the changes in

Accepted Answer

Both A & B

Answer

Viscosity with concentration

Answer

Degree of ideality of the solution

Answer

Neither A nor B

Question 4

Lewis number (Le) is

Accepted Answer

Sc × Pr

Answer

Pr × St

Answer

Sh × Pr

Answer

St × Sh

Question 5

Raoult's law applies to the

Accepted Answer

Solvents

Answer

All liquid solutions

Answer

Non-ideal solution only

Answer

Non-volatile solute

Question 6

In case of non-ideal gases and liquids, the molal diffusivity

Accepted Answer

Is independent of pressure

Answer

Varies inversely as the pressure

Answer

Varies directly as the pressure

Answer

Is equal to the volumetric diffusivity

Question 7

The individual mass transfer co-efficients (moles/m 2 .s) for absorption of a solute from a gas mixture into a liquid solvent are, K L = 4.5 and K G = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling?

Accepted Answer

Gas side

Answer

Liquid side

Answer

Interfacial

Answer

Both liquid and gas side

Question 8

Cox chart, which is useful in the design of distillation column particularly for petroleum hydrocarbons, is a plot of (where, P = vapor pressure, T = temperature)

Accepted Answer

Log P vs . T

Answer

Log P vs. log T

Answer

T vs . P

Answer

P vs . log T

Question 9

The Kundsen diffusivity is proportional to (where, T = absolute temperature)

Accepted Answer

$$\sqrt {	ext{T}} $$

Answer

T 2

Answer

T

Answer

T 4