Mass Transfer MCQs

Question 1

For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.

Accepted Answer

Pure component is represented by the apex

Answer

Binary mixture is represented by the apex

Answer

Binary mixture is represented by any point inside

Answer

Ternery mixture is represented by the sides

Question 2

Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number.

Accepted Answer

Schmidt

Answer

Sherwood

Answer

Peclet

Answer

Stanton

Question 3

Heat sensitive materials with very high latent heat of vaporisation may be economically separated using

Accepted Answer

Liquid extraction

Answer

Distillation

Answer

Evaporation

Answer

Absorption

Question 4

The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around

Accepted Answer

1

Answer

0.24

Answer

3.97

Answer

600

Question 5

Pick out the wrong statement.

Accepted Answer

Azeotropes obey Raoult's law at all temperature

Answer

The mole fraction of solute is directly proportional to the molality of a 'dilute' solution

Answer

For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is nonlinear in the case of steady state unimolal unidirectional diffusion

Answer

The relative volatility of a binary mixture at the azeotropic composition is 1

Question 6

Which of the following operations does not involve leaching?

Accepted Answer

Removing nicotine from its water solution by kerosene

Answer

Dissolving gold from ores

Answer

Dissolving pharmaceutical products from bark or roots

Answer

Dissolving sugar from the cells of the beet

Question 7

According to Chilton-Colburn analogy for mass transfer, $${{	ext{N}}_{{	ext{St}}}}.{{	ext{N}}_{{	ext{Sc}}}}^{\frac{2}{3}}$$ is equal to

Accepted Answer

$$\frac{{	ext{f}}}{2}$$

Answer

f

Answer

2f

Answer

$$\frac{1}{{	ext{f}}}$$

Question 8

The Knudsen diffusivity is dependent on the

Accepted Answer

Molecular velocity and por radius of the catalyst

Answer

Molecular velocity only

Answer

Pore radius of the catalyst only

Answer

Molecular mean free path only

Question 9

In a counter-current extractor, as the axial mixing increases, the extraction efficiency

Accepted Answer

Decreases

Answer

Increases

Answer

Remains unchanged

Answer

Depends on the pressure of the system