Mass Transfer MCQs

Question 1

The drying time between fixed moisture content within diffusion controlled 'falling rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid)

Accepted Answer

T 2

Answer

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

Answer

T

Answer

T 3

Question 2

For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of H₂/k y .C z is around

Accepted Answer

1

Answer

0.6

Answer

0.24

Answer

0.72

Question 3

__________ is the separation technique used for desalination of sea water.

Accepted Answer

Reverse osmosis

Answer

Thermal diffusion

Answer

Adsorption

Answer

Absorption

Question 4

Acetic acid will be most economically separated from a dilute solution of acetic acid in water by

Accepted Answer

Solvent extraction

Answer

Continuous distillation

Answer

Evaporation

Answer

Absorption

Question 5

Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.

Accepted Answer

Rotary

Answer

Vacuum

Answer

Tunnel

Answer

Tray

Question 6

Azeotropism for ethyl alcohol-water system disappears by

Accepted Answer

Decreasing pressure

Answer

Increasing temperature

Answer

Increasing pressure

Answer

No means

Question 7

A mixture of 10% C 6 H 6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.

Accepted Answer

18.7

Answer

21.7

Answer

20

Answer

27.3

Question 8

Pick out the system with maximum boiling azeotrope at 1 atm.

Accepted Answer

Acetone chloroform

Answer

Ethyl alcohol-water

Answer

Benzene-ethyl alcohol

Answer

None of these

Question 9

L/mG is the expression for

Accepted Answer

Absorption factor

Answer

Brinkman number

Answer

Slope of operating line in absorber

Answer

Slope of operating line in stripper