Top 550+ Solved Mass Transfer MCQ Questions Answer
Q. Capacity of a rotary dryer depends on its
a. rpm
b. Inclination with ground surface
c. Both (A) and (B)
d. Neither (A) nor (B)
Q. The most common packing used in industrial operations is __________ rings.
a. Raschig
b. Lessing
c. Cross-partition
d. Single spiral
Q. Refractory bricks are usually dried in a __________ dryer.
a. Tray
b. Tunnel
c. Conveyor
d. Festoon
Q. Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate.
a. Increases
b. Decreases
c. Does not affect
d. Exponentially increases
Q. The binary diffusivity in gases at atmospheric conditions is about
a. 10-9 cm/sec
b. 10-1 cm2/sec
c. 10-3 sec/cm
d. 10-4 cm2/sec2
Q. For absorbers, high pressure drop results in
a. Increased efficiency
b. Decreased efficiency
c. High operating cost
d. Better gas liquid contact
Q. __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.
a. Dew point
b. Bubble point
c. Dry bulb temperature
d. Wet bulb temperature
Q. Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C?
a. Humidification only
b. Heating only
c. Both heating and humidification
d. Evaporative cooling
Q. The velocity, concentration and temperature boundary, for the boundary layer developmenton a flat plate during connective mass transfer will be same, if
a. NSc = 1
b. NSc = NPr = NLe
c. NPr = NLe
d. NSc = NLe
Q. Pick out the wrong statement. Generally for physical adsorption, a gas of
a. Higher molecular weight is adsorbed in preference to a gas of low molecular weight
b. High critical temperature is adsorbed in preference to a gas of low critical temperature
c. Low volatility is adsorbed in preference to a gas of high volatility
d. None of these
Q. Co-current absorbers are usually used when the gas to be dissolved in the liquid is
a. Sparingly soluble
b. Highly soluble
c. A pure substance
d. A mixture
Q. Molecular sieves are regenerated by heating to __________ °C.
a. < 150
b. 200-330
c. > 500
d. > 1000
Q. In triangular co-ordinates, the ternary composition point falls __________ of the triangle.
a. In the corners
b. Inside
c. On the sides
d. None of these
Q. When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30°C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,
a. As the acetone concentration increases, the solubility curves approach each other
b. Both the phases become iden called the plait point
c. The distribution curve which is a plot between x (acetone concentration in one phase) and y (acetone concentration in other phase) is analogous to x-y curve used in distillation and absorption terminates on the x = y diagonal at the concentration of the plait point
d. All (A), (B) and (C)
Q. During sensible cooling process
a. Relative humidity decreases
b. Relative humidity increases
c. Wet bulb temperature decreases
d. Both (B) and (C)