Mass Transfer MCQs

Question 1

Which of the following is an undesirable characteristic for the solvent used in gas absorption?

Accepted Answer

None of these

Answer

Low vapor pressure

Answer

Low viscosity

Answer

High gas solubility

Question 2

Reverse osmosis is also called

Accepted Answer

Ultrafiltration

Answer

Dialysis

Answer

Electrodilysis

Answer

Diffusion

Question 3

At constant pressure, with increase of temperature, the dew point will

Accepted Answer

Increase

Answer

Decrease

Answer

Remain unchanged

Answer

Increase/decrease ; depends on the temperature

Question 4

Plate efficiency in a distillation column is reduced due to the __________ of liquid.

Accepted Answer

All of the above

Answer

Entrainment

Answer

Foaming

Answer

Weeping & dumping

Question 5

For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams

Accepted Answer

Increases

Answer

Decreases

Answer

Remains unaffected

Answer

Passes through a maximum

Question 6

Pick out the correct statement.

Accepted Answer

Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of non-ideal binary system by distillation

Answer

A sharp decrease in pressure drop is an indication of flooding in a distillation coloumn

Answer

Solvent used in extractive distillation should be of high volatility

Answer

Flash distillation is suitable for separating components which have very close boiling temperature

Question 7

Pick out the wrong statement:

Accepted Answer

In case of a stripper, the equilibrium curve is always below the operating line

Answer

Absorption factor is constant, when the equilibrium and operating lines are straight

Answer

In case of an absorber, the operating line is always above the equilibrium curve

Answer

In the absorption of low solubility gases, the liquid film is the controlling resistance

Question 8

Steady state equimolal counter diffusion is encountered in

Accepted Answer

Separation of a binary mixture by distillation

Answer

Absorption of NH 3 from air by water

Answer

All liquid-liquid diffusion systems

Answer

All of the above

Question 9

Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 × 10 -3 kg mole/m 2 .s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m 2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is

Accepted Answer

8.5 × 10 -4

Answer

5.6 × 10 -4

Answer

5.6 × 10 -3

Answer

8.5 × 10 -3