Mass Transfer MCQs

Question 1

In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTU OG __________ the absorption factor.

Accepted Answer

Both A and B

Answer

Increases with increase in

Answer

Is one at unity value of

Answer

Neither A nor B

Question 2

Fenske equation determines the

Accepted Answer

Minimum number of theoretical plates

Answer

Maximum number of ideal plates

Answer

Height of the distillation column

Answer

Optimum reflux ratio

Question 3

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty?

Accepted Answer

Bubble cap tower

Answer

Grid tray tower

Answer

Perforated tray tower

Answer

Wetted wall tower

Question 4

Which of the following has the same dimension as mass diffusivity?

Accepted Answer

Both A & B

Answer

Momentum flux

Answer

Kinematic viscosity

Answer

Thermal diffusivity

Question 5

__________ is used as an 'entrainer' for the separation of acetic acid-water mixture by distillation.

Accepted Answer

Butyl acetate

Answer

Furfural

Answer

Benzol

Answer

Hexane

Question 6

Which of the following remains constant during evaporative cooling process with recirculated water supply?

Accepted Answer

Wet bulb temperature

Answer

Relative humidity

Answer

Partial pressure of vapour

Answer

None of these

Question 7

As the reflux ratio increases, the slope of the operating line for rectifying section

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

Data insufficient, cannot be predicted

Question 8

The diffusivity (D) in a binary gas mixture is related to the pressure (P) as

Accepted Answer

$${	ext{D}} \propto \frac{1}{{	ext{P}}}$$

Answer

$${	ext{D}} \propto {{	ext{P}}^{0.5}}$$

Answer

$${	ext{D}} \propto \frac{1}{{{{	ext{P}}^{0.5}}}}$$

Answer

$${	ext{D}} \propto \frac{1}{{{{	ext{P}}^{1.5}}}}$$

Question 9

__________ equation applies to diffusivities in liquids.

Accepted Answer

Gilliland

Answer

Hirschfelder

Answer

Wilke and Chang

Answer

None of these