Mass Transfer MCQs

Question 1

With increase in temperature, the leaching rate increases due to

Accepted Answer

Both A & B

Answer

Decreased liquid viscosity

Answer

Increased diffusivity

Answer

Neither A nor B

Question 2

Steam distillation is not recommended to be used, if the

Accepted Answer

Azeotropic mixture is to be separated and the final product is miscible with water

Answer

Liquids decompose, if distilled directly at atmospheric pressure

Answer

Material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature

Answer

Material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature

Question 3

Weight of 1 m 3 of humid air as compared to 1 m 3 of dry air, under the same conditions, is

Accepted Answer

Less

Answer

More

Answer

Same

Answer

Unpredictable

Question 4

Make up water is required in a cooling tower to replace the water lost by

Accepted Answer

All of the above

Answer

Evaporation

Answer

Drift

Answer

Blowdown and leakage

Question 5

A good solvent used for absorption should not have very high

Accepted Answer

All of the above

Answer

Viscosity

Answer

Vapor pressure

Answer

Freezing point

Question 6

Diffusion in concentrated solutins differs from that in dilute solutions, because of the change in the __________ with the concentration of the solution.

Accepted Answer

Both A & B

Answer

Degree of ideality

Answer

Viscosity

Answer

Neither A nor B

Question 7

Mass transfer co-efficient 'K' according to penetration theory varies with mass diffusivity as

Accepted Answer

D 0.5

Answer

D

Answer

$$\frac{1}{{	ext{D}}}$$

Answer

D 1.5

Question 8

Molecular diffusion is caused by the

Accepted Answer

Thermal energy of the molecules

Answer

Transfer of molecules from low concentration to high concentration region

Answer

Activation energy of the molecules

Answer

Potential energy of the molecules

Question 9

If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is

Accepted Answer

1

Answer

0

Answer

< 1

Answer

> 1