Top 550+ Solved Mass Transfer MCQ Questions Answer
Q. Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.)
a. (1 + Ro) = Ro/Ri
b. (1 - Ro) = Ro/Ri
c. (1 + Ri) = Ro/Ri
d. (1 - Ri) = Ro/Ri
Q. Even though bubble cap towers are very effective for humidification operation, they are not used commonly in industries, because of the
a. High evaporation losses of water
b. High pressure drop of the gas
c. Difficulty in its fabrication
d. None of these
Q. In case of constant underflow extraction operation, the __________ at all solute concentration.
a. Solids are drained to the same extent
b. Ratio of the insoluble to solution is constant
c. Both (A) & (B)
d. Neither (A) nor (B)
Q. Which of the following has the same dimension as mass diffusivity?
a. Momentum flux
b. Kinematic viscosity
c. Thermal diffusivity
d. Both (B) and (C)
Q. Packed column distillation is limited to the column __________ metres.
a. Height < 6
b. Diameter < 0.6
c. Both (A) & (B)
d. Neither (A) nor (B)
Q. Which of the following decreases during evaporative cooling process with recirculated water supply?
a. Wet bulb temperature
b. Relative humidity
c. Partial pressure of vapour
d. None of these
Q. During constant rate period, the rate of drying decreases with the
a. Decrease in air temperature
b. Increase in air humidity
c. Both (A) and (B)
d. Neither (A) nor (B)
Q. At what percentage (by volume) of alcohol composition, it forms an azeotrope with water?
a. 90
b. 91.5
c. 95
d. 99
Q. Which of the following is considered equivalent to one theoretical stage in Mc-Cabe Thiele's method?
a. Partial condenser
b. Total condenser
c. Reboiler
d. Both (B) and (C)
Q. Steam distillation is not recommended to be used, if the
a. Azeotropic mixture is to be separated and the final product is miscible with water
b. Liquids decompose, if distilled directly at atmospheric pressure
c. Material cannot be distilled by indirect heating even under low pressure, because of the high boiling temperature
d. Material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature
Q. It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The equilibrium moisture content of the solid is 5%).
a. 15 min
b. 51 min
c. 71 min
d. 94 min
Q. In Azeotropic mixture, the equilibrium vapour composition is
a. More than liquid composition
b. Less than liquid composition
c. Same as liquid composition
d. Independent of pressure
Q. In rectifying section of a continuous distillation column, the
a. Vapour is enriched with low boilers
b. Vapour is enriched with high boilers
c. Liquid is stripped of high boilers
d. None of these
Q. The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives
a. Low pressure drop and high hold up
b. High pressure drop and low hold up
c. Low pressure drop and low hold up
d. High pressure drop and high hold up