Mass Transfer

461.The film penetration model of mass transfer was enunciated by

1. Gilliland
2. Toor and Marcello
3. Stefan
4. Fick

View answer

462.The Hatta number is important in

1. Multi-component distillation
2. Binary distillation
3. Gas absorption without chemical reaction
4. Gas absorption with chemical reaction

View answer

463.The humid volume may be increased by increasing the

1. Temperature at constant humidity
2. Humidity at constant temperature
3. Both (A) and (B)
4. Neither (A) nor (B)

View answer

464.The individual mass transfer co-efficients (moles/m²s) for absorption of a solute from a gas mixture into a liquid solvent are, K_L = 4.5 and K_G = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling?

1. Liquid side
2. Gas side
3. Interfacial
4. Both liquid and gas side

View answer

465.The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m²/m3)

1. 500
2. 1200
3. 900
4. 800

View answer

466.The Knudsen diffusivity is dependent on the

1. Molecular velocity only
2. Pore radius of the catalyst only
3. Molecular mean free path only
4. Molecular velocity and pore radius of the catalyst

View answer

467.The Knudsen diffusivity is proportional to (where, T = absolute temperature)

1. √T
2. T²
3. T
4. T⁴

View answer

468.The main reason for dividing a tall packed tower into series of small towers is to

1. Minimise the overall pressure drop
2. Avoid flooding
3. Reduce liquid hold up
4. Avoid channelling

View answer

469.The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = _________

1. 1
2. 0.5
3. 10
4. 0

View answer

470.The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which 'D' is the diffusivity of solute, is

1. D/a
2. D/2a
3. Proportional to √D
4. Dependent on the Reynolds number

View answer