Mass Transfer question bank (Question Bank . Paper 73) Section- 10

1. Freundlich equation applies to the adsorption of solute from

1. dilute solutions, over a small concentration range..
2. gaseous solutions at high pressure.
3. concentrated solutions.
4. none of these.

2. The minimum number of theoretical plates is required for achieving a given separation in distillation column with

1.total reflux
2. zero reflux
3. infinite reflux
4. None of these

3. Pick out the wrong statement. Generally, for physical adsorption, a gas of

1. higher molecular weight is adsorbed in preference to a gas of low molecular weight..
2. less than that computed for ideality.
3. less than the sum of the vapour pressure of the components.
4. none of these.

4.In extractive distillation, solvent is

1.of high volatility.
2. present in overhead stream.
3. added to alter the relative volatility of the mixture.
4. of high viscosity to give high tray efficiency.

5. When the mixture to be distilled has a very high boiling point and the product material is heat sensitive, the separation technique to be used is __________ distillation

1. azerotropic
2. steam
3. continues
4. None of the above

6.Which of the following unit operations makes use of Thiele-Geddes equation?

1. Liquid-liquid extraction
2.Solid-liquid extraction
3. Multicomponent distillation
4. Multicomponent absorption with chemical reaction

7. Steam distillation is used to

1. increase the efficiency of separation.
2. increased reboiler load
3.reduce the number of plates.
4. None of these.

8. Azeotropic distillation is employed to separate

1. constant boiling mixture.
2. high boiling mixture
3. heat sensitive materials.
4. mixture with very high relative volatility

9. In distillation columns, the number of bubble caps per tray primarily depends upon the

1. allowable liquid velocity.
2. allowable gas velocities.
3. feed composition.
4. allowable gas and liquid velocities.

10. For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause __________ plate requirement.

1. marginal decrease in the number of
2. major decrease in the number of
3. no change in theoretical
4. None of these

11. The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are

1. parallel
2. straight
3. neither parallel nor straight
4. both parallel and straight

12.The fixed cost of a distillation column at minimum reflux ratio is

1. minimum
2. None of these
3.infinite
4. optimum

13. Design calculation for multiple component distillation is done by

1. Ponchon-Savarit method
2. Mccabe-Thiele method
3. tray to tray calculations.
4. enthalpy concentration method

14.As complete saturation of an adsorbent is approached, the differential heat of adsroption approaches

1. none of these
2. zero
3. that of normal condensation
4. integral heat of adsorption

15. With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency

1. increase
2.decrease
3. remain same
4. may increase or decrease ; depends on individual design