Top 550+ Solved Mass Transfer MCQ Questions Answer
Q. With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________, if the conduction and radiation through the solid are negligible.
a. Increases
b. Decreases
c. Remain same
d. Increases linearly
Q. During the constant rate period of drying of a solid,
a. Increased air humidity decreases the rate of drying
b. Increasing the air temperature decreases the drying rate
c. Surface evaporation of unbound moisture occurs
d. None of these
Q. Large scale drying of wheat is done in a __________ dryer.
a. Fluidised bed
b. Spouted bed
c. Tray
d. Vacuum rotary
Q. Humidification involves mass transfer between a pure liquid phase and a fixed gas, which is
a. Insoluble in the liquid
b. Soluble in the liquid
c. Non-ideal in nature
d. At a fixed temperature
Q. With increase in temperature, the leaching rate increases due to
a. Decreased liquid viscosity
b. Increased diffusivity
c. Both (A) and (B)
d. Neither (A) nor (B)
Q. As the reflux ratio, in a continuous counter-current extraction is increased, the number of stages
a. Increase
b. Decrease
c. Remain unchanged
d. Can either increase or decrease, depends on the system
Q. Large scale drying of sugar is done in a __________ dryer.
a. Spouted bed
b. Tray
c. Rotary
d. Truck
Q. Though, theoretically the adsorption & desorption isotherms is expected to coincide but sometimes at least a part of the isotherms does not coincide and this phenomenon is known as adsorption hysteresis. In such cases, the desorption equilibrium pressure is __________ that obtained for adsorption.
a. Lower than
b. Higher than
c. Same as
d. Either same or higher than
Q. Reboiler is considered as one theoretical plate, because
a. Of the assumption that vapour and liquid leaving the reboiler are in equilibrium
b. Vapour is recycled to the column
c. Reboiler itself contains one plate
d. None of these
Q. In an absorption column, the flooding velocity for random packing is __________ that for stacked/regular packing.
a. Greater than
b. Smaller than
c. Equal to
d. Either (A), or (B); depends on the type of packing
Q. 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/m2 .s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is:
a. 5.6 × 10-4
b. 8.5 × 10-4
c. 5.6 × 10-3
d. 8.5 × 10-3
Q. In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the __________ number.
a. Lewis
b. Grashoff
c. Sherwood
d. None of these
Q. When the gas to be dissolved in liquid is a/an __________ then normally co-current adsorber are used.
a. Mixture of two gases
b. Pure gas
c. Ideal gas
d. Sparingly soluble gas