Practice Test: Question Set - 10
1. Lewis number (Le) is
- (A) Sc × Pr
- (B) Pr × St
- (C) Sh × Pr
- (D) St × Sh
2. Which is not concerned directly with mass transfer?
- (A) Schmidt number
- (B) Sherwood number
- (C) Lewis
relationship
- (D) Froude number
3. Most important factor to be considered in the selection of packings for absorbers is the __________ of packing.
- (A) Size
- (B) Durability
- (C) Porosity
- (D) Cost
4. For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause __________ plate requirement.
- (A) No change in
theoretical
- (B) Marginal decrease in
the number of
- (C) Major decrease in the
number of
- (D) None of these
5. Experimental determination of __________ is done by wetted wall column method.
- (A) Diffusion
co-efficient
- (B) Mass transfer
co-efficient
- (C) NTU
- (D) None of these
6. Ammonia present in the coke oven gas is removed by washing with
- (A) Caustic solution
- (B) Dilute ammoniacal
liquor
- (C) Dilute HCl
- (D) Ethanolamine
7. Which of the following provides maximum contact surface for a liquid-vapor system?
- (A) Packed tower
- (B) Bubble-cap plate
column
- (C) Sieve-plate column
- (D) Wetted wall column
8. At the boiling point of the liquid at the prevailing pressure, the saturated absolute humidity becomes
- (A) 1
- (B) 0
- (C) ∞
- (D) None of these
9. Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ column.
- (A) Spray
- (B) Packed
- (C) Bubble cap plate
- (D) Wetted wall
10. Which of the following is directly concerned with Psychrometry?
- (A) Lewis relationship
- (B) Galileo number
- (C) Weber number
- (D) Dean number
11. In the layout plan for a vacuum distillation unit, operating at 60 mm Hg, supported by a barometric condenser, the appropriate place for the location of vacuum drum for collecting the distillate will be
- (A) At ground level
- (B) 2 meters above the
ground
- (C) 5 meters above ground
- (D) 10 meters above
ground
12. Which of the following is an undesirable property in a tower packing?
- (A) Large surface per
unit volume
- (B) Large free
cross-section
- (C) Low weight per unit
volume
- (D) Large weight of
liquid retained
13. High pressure at the bottom of a distillation tower handling heat sensitive materials results in
- (A) Thermal decomposition
of bottoms
- (B) Increased relative
volatility
- (C) Erosion of the tower
- (D) Very efficient
operation
14. Steady state equimolal counter diffusion is encountered in
- (A) Separation of a
binary mixture by distillation
- (B) Absorption of NH3 from
air by water
- (C) All liquid-liquid
diffusion systems
- (D) All liquid-solid
diffusion systems
15. Minimum reflux ratio in a distillation column results in
- (A) Optimum number of
trays
- (B) Minimum reboiler size
- (C) Maximum condenser
size
- (D) Minimum number of
trays
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