Mass Transfer MCQs

Question 1

Pick out the wrong statement.

Accepted Answer

Vanderwall adsorption is also called chemisorption

Answer

With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V ratio

Answer

The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction

Answer

Natural draft cooling towers are made of ferro-concrete and its cross-section is wider at the bottom

Question 2

Make up water is supplied during cooling tower operation to compensate for water losses due to

Accepted Answer

All of the above

Answer

Evaporation

Answer

Blowdown

Answer

Entrainment

Question 3

Separation of two or more components of a liquid solution can not be achieved by

Accepted Answer

Absorption

Answer

Fractional crystallisation

Answer

Liquid extraction

Answer

Evaporation

Question 4

Chemisorption compared to physical absorption has

Accepted Answer

Increased utilisation of stagnant zones of the liquid phase

Answer

Lower adsorption rate

Answer

Lower capacity of the solvent for the solute gas

Answer

None of these

Question 5

Pick out the wrong statement. Raoult's law does not apply, when the

Accepted Answer

Component molecules are nonpolar

Answer

Size of component molecules are not equal

Answer

Attractive forces between like and unlike molecules in the solution are approximately equal

Answer

Chemical combination or molecular association between unlike molecules takes place in the formation of solution

Question 6

The relative saturation of an unsaturated mixture of gas and vapor is independent of the

Accepted Answer

None of these

Answer

Nature of the vapor

Answer

Temperature of the mixture

Answer

Composition of the mixture

Question 7

Steam distillation is used to

Accepted Answer

Avoid thermal decomposition of a component

Answer

Reduce the number of plates

Answer

Increase the efficiency of separation

Answer

Increase the total pressure of distillation

Question 8

Lewis number, which is important in problems involving simultaneous heat and mass transfer, is the ratio of

Accepted Answer

Thermal diffusivity to mass diffusivity

Answer

Mass diffusivity to momentum diffusivity

Answer

Momentum diffusivity to thermal diffusivity

Answer

None of these

Question 9

Rate of adsorption increases as the

Accepted Answer

Temperature decreases

Answer

Temperature increases

Answer

Pressure decreases

Answer

Size of adsorbent increases