Practice Test: Question Set - 15
1. 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)
2. At what percentage (by volume) of alcohol composition, it forms an azeotrope with water?
- (A) 90
- (B) 91.5
- (C) 95
- (D) 99
3. 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)
4. 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
5. 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
6. Which of the following liquid temperature (T) vs. vapor-gas mixture enthalpy (H) diagram is valid for humidification operation?
7. In Azeotropic mixture, the equilibrium vapor composition is
- (A) More than liquid
composition
- (B) Less than liquid
composition
- (C) Same as liquid
composition
- (D) Independent of
pressure
8. In rectifying section of a continuous distillation column, the
- (A) Vapor is enriched
with low boilers
- (B) Vapor is enriched
with high boilers
- (C) Liquid is stripped of
high boilers
- (D) None of these
9. 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
10. Diameter of raschig rings used in packed tower in industry is normally around __________ inches.
- (A) 2
- (B) 8
- (C) 12
- (D) 18
11. The ratio of Murphree plate efficiency to point efficiency is 1 in a __________ flow model.
- (A) Plug
- (B) Perfectly mixed
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
12. Plate efficiency
- (A) Is a function of the
mass transfer between liquid and vapour
- (B) Increases due to
foaming
- (C) Increases due to
liquid entrainment
- (D) Increases due to
weeping and dumping of liquid
13. Weeping in a distillation column
- (A) Increases tray
efficiency
- (B) Provides large
interfacial surface for mass transfer
- (C) Results due to very
high gas velocity
- (D) Results due to very
low gas velocity
14. The expression, y(1 - x)/x(1 - y) is for
- (A) Absorption factor
- (B) Relative volatility
- (C) Selectivity
- (D) Murphree efficiency
15. The process employing desorption of the absorbed solute by a solvent is called
- (A) Elution
- (B) Osmosis
- (C) Reverse osmosis
- (D) Sublimation