171. The expression, y(1 – x)/x(1 – y) is for
Absorption factor
Relative volatility
Selectivity
Murphree efficiency
✅ The correct answer is option B.
Mass Transfer MCQs
172. 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,
As the acetone concentration increases, the solubility curves approach each other
Both the phases become identical at a particular common point on both the solubility curves called the plait point
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 termina
All of the above
✅ The correct answer is option D.
173. Can a cooling tower cool water below the wet bulb temperature of inlet air?
Yes
No
Yes ; but height of cooling tower will be prohibitively high
Yes ; but the air flow rate should be excessively high
✅ The correct answer is option B.
174. Blowdown in a cooling tower
Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities
Increases the scale forming tendencies of water
Is undesirable
All of the above
✅ The correct answer is option A.
175. 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?
Humidification only
Heating only
Both heating and humidification
Evaporative cooling
✅ The correct answer is option C.
176. Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure.Nitrobenzene will distill off __________ °C.
At < 100
At > 210.6
Between 100 and 210
None of these
✅ The correct answer is option A.
177. For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as
Re0.33
Re0.53
Re0.83
Re
✅ The correct answer is option C.
178. Alcohol is dehydrated using __________ distillation.
Extractive
Azeotropic
Steam
Molecular
✅ The correct answer is option B.
179. In rectifying section of a continuous distillation column, the
Vapour is enriched with low boilers
Vapour is enriched with high boilers
Liquid is stripped of high boilers
None of these
✅ The correct answer is option B.
180. Back-trapping in a distillation column
Increases tray efficiency
Decreases tray efficiency
Reduces pressure drop
Is desirable, as it provides improved vapour-liquid contact
✅ The correct answer is option B.