Mass Transfer MCQs

Question 1

In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the __________ number.

Accepted Answer

Lewis

Answer

Grashoff

Answer

Sherwood

Answer

None of these

Question 2

The diffusivity (D) in a binary gas mixture is related to the temperature (T) as

Accepted Answer

D ∝ T1.5

Answer

D ∝ T

Answer

D ∝ T0.5

Answer

D ∝ T2

Question 3

In an operating distillation column, the

Accepted Answer

Driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column

Answer

Vapors and liquids are at their dew point and bubble point respectively

Answer

Driving force for the liquid flow is its specific weight

Answer

Highest temperature is encountered at the top of the column

Question 4

If G = insoluble gas in gas stream and L = non-volatile solvent in liquid stream, then the slope of the operating line for the absorber is

Accepted Answer

$$\frac{{	ext{L}}}{{	ext{G}}}$$

Answer

$$\frac{{	ext{G}}}{{	ext{L}}}$$

Answer

Always < 1

Answer

None of these

Question 5

Pick out the correct statement.

Accepted Answer

Electrodylsis is used in the manufacture of NaOH

Answer

Dialysis process is used for the production of fresh water from brine

Answer

Electrodylsis is used for the refin-ning/purification of petrol

Answer

Both B and C

Question 6

__________ diffusion is used for separating the isotopes of methane.

Accepted Answer

Thermal

Answer

Pressure

Answer

Concentration

Answer

Force

Question 7

McCabe-Thiele method of binary distillation does not assume that the

Accepted Answer

None of these

Answer

Sensible heat changes are negligible compared with latent heat changes

Answer

Molar latent heats of all components are equal

Answer

Heat of mixing is negligible

Question 8

Which of the following parameters remains almost constant during adiabatic saturation of unsaturated air?

Accepted Answer

Wet bulb temperature

Answer

Dry bulb temperature

Answer

Dew point

Answer

None of these

Question 9

Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maximum equilibrium moisture?

Accepted Answer

Bamboo

Answer

Anthracite coal

Answer

Rag paper

Answer

Inorganic solids