Category: Mass Transfer

Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are ?

Hamad Mass Transfer 04/05/2024

0

A. 4
B. 8
C. 9
D. 10

A mixture of 10% C6H6 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?

Hamad Mass Transfer 28/04/2024

0

A. 21.7
B. 20
C. 27.3
D. 18.7

If Rm is the minimum reflux ratio, the optimum reflux ratio may be around _________________ Rm ?

Hamad Mass Transfer 28/04/2024

0

A. 1.2 to 1.5
B. 2.5 to 3
C. 3 to 4
D. 5

The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives___________________?

Hamad Mass Transfer 12/04/2024

0

A. Low pressure drop and high hold up
B. High pressure drop and low hold up
C. Low pressure drop and low hold up
D. High pressure drop and high hold up

Percentage saturation is _______________ the relative saturation?

Hamad Mass Transfer 11/04/2024

0

A. Always smaller than
B. Always greater than
C. Not related to
D. None of these

Alcohol is dehydrated using _______________________ distillation?

Hamad Mass Transfer 08/04/2024

0

A. Extractive
B. Azeotropic
C. Steam
D. Molecular

The commonly used solvent in supercritical extraction is_____________________?

Hamad Mass Transfer 08/04/2024

0

A. Methyl ethyl ketone
B. Water
C. Carbon tetrachloride
D. Carbon dioxide

Raschig ring made of porcelain cannot be used for treating concentrated___________________?

Hamad Mass Transfer 24/03/2024

0

A. Hydrochloric acid
B. Nitric acid
C. Alkalis
D. Sulphuric acid

Absorption (liquid-gas system) with evolution of heat as compared to isothermal absorption results in_________________?

Hamad Mass Transfer 13/03/2024

0

A. Decreased solute solubility
B. Large minimum liquid to gas (L/G) ratio
C. Large number of trays
D. All A., B. and C.

An alkaline solution is used to reduce the concentration of carbon dioxide in a stream from 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is ?

Hamad Mass Transfer 10/03/2024

0

A. 9.21
B. 4.605
C. 100
D. 0.001