521. Total reflux in a distillation operation requires minimum
Reboiler load
Number of plates
Condenser load
All of the above
✅ The correct answer is option B.
Mass Transfer MCQs
522. The ratio of Murphree plate efficiency to point efficiency is 1 in a __________ flow model.
Plug
Perfectly mixed
Both A & B
Neither A nor B
✅ The correct answer is option B.
523. With increase in temperature, the leaching rate increases due to
Decreased liquid viscosity
Increased diffusivity
Both A & B
Neither A nor B
✅ The correct answer is option C.
524. The term “cooling range” in a cooling tower refers to the difference in the temperature of
Cold water leaving the tower and the wet bulb temperature of the surrounding air
Hot water entering the tower and the wet bulb temperature of the surrounding air
Hot water entering the tower and the cooled water leaving the tower
None of these
✅ The correct answer is option C.
525. During constant rate period, the rate of drying decreases with the
Decrease in air temperature
Increase in air humidity
Both A & B
Neither A nor B
✅ The correct answer is option C.
526. Rotary dryers cannot handle __________ materials.
Free flowing
Dry
Sticky
Grannular
✅ The correct answer is option C.
527. Which of the following is the most suitable for extraction in a system having very low density difference?
Mixer-settler extractor
Centrifugal extractor
Pulsed extractor
Packed extraction tower
✅ The correct answer is option B.
528. The individual mass transfer co-efficients (moles/m² . s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ?
Liquid side
Gas side
Interfacial
Both liquid and gas side
✅ The correct answer is option B.
529. Penetration theory relates the average mass transfer co-efficient (K) with diffusivity (D) as
K ∝ D
K ∝ √D
K ∝ D1.5
K ∝ D2
✅ The correct answer is option B.
530. In a moderately sized packed absorption tower, channeling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter
> 4 :1
< 8 : 1
> 8:1
< 6:1
✅ The correct answer is option C.