Practice Test: Question Set - 32
1. Relative humidity is the ratio of the
- (A) Partial
pressure of the vapor to the vapor pressure of the liquid at room temperature
- (B) Partial
pressure of the vapor to the vapor pressure of the liquid at gas temperature
- (C) Actual
humidity to saturation humidity
- (D) None of these
2. In the absorption of ammonia in water, the main resistance to absorption is by the __________ phase.
- (A) Liquid
- (B) Gas
- (C) Both
(a) & (b)
- (D) Neither (a) nor (b)
3. In paper industry, paper is dried in a __________ dryer.
- (A) Tunnel
- (B) Heated cylinder
- (C) Conveyor
- (D) Festoon
4. Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around __________ inches.
- (A) 5
- (B) 30
- (C) 60
- (D) 100
5. Which of the following plays an important role in problems of simultaneous heat and mass transfer?
- (A) Lewis number
- (B) Schmidt
number
- (C) Prandtl
number
- (D) Sherwood
number
6. In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimized by taking the ratio of tower diameter to packing diameter
- (A) > 4 : 1
- (B) < 8 : 1
- (C) > 8 : 1
- (D) < 6 : 1
7. If f = moles of vapor present per mole of feed, then the slope of feed line is (McCabe-Thiele method)
- (A) (1 - f)/f
- (B) - (f - 1)/f
- (C) -1/f
- (D) -f/(1 - f)
8. Pick out the wrong statement.
- (A) The
operating line always lies above the equilibrium solubility curve in case of a
single component absorber
- (B) The
operating line always lies below the equilibrium solubility curve in case of a
single component stripper
- (C) The
operating pressure in solvent extraction system should be below vapor pressures
of all components
- (D) The
solubility of a particular gas in ideal solution in any solvent is always the
same
9. Mass transfer co-efficient of liquid is
- (A) Affected
more by temperature than that for gases
- (B) Affected
much less by temperature than that for gases
- (C) Not
affected by the temperature
- (D) None of these
10. Heat sensitive materials with very high latent heat of vaporization may be economically separated using
- (A) Liquid
extraction
- (B) Distillation
- (C) Evaporation
- (D) Absorption
11. The reciprocal of stripping factor is termed as
- (A) Selectivity index
- (B) Relative
volatility
- (C) Absorption
factor
- (D) Murphree
efficiency
12. A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,
- (A) Composition
of vapors and that of liquid do not vary throughout the column
- (B) Reboiler load and
condenser load are minimum
- (C) The
top and bottom compositions are unchanged with and without total reflux
- (D) The
top and bottom compositions correspond to the maximum enrichment available
13. In distillation columns, the number of bubble caps per tray primarily depends upon the
- (A) Allowable liquid
velocity
- (B) Allowable gas
velocity
- (C) Allowable gas and
liquid velocities
- (D) Feed composition
14. Batch tray dryers suffers from the disadvantage of
- (A) High maintenance cost
- (B) Non-uniform & low
production rate
- (C) High labour cost
& low heat economy
- (D) All 'a', 'b' &
'c'
15. For absorbing a sparingly soluble gas in a liquid
- (A) Gas side mass
transfer co-efficient should be increased
- (B) Liquid
side mass transfer co-efficient should be increased
- (C) Liquid side mass
transfer co-efficient should be decreased
- (D) Mass transfer
co-efficient must be kept constant
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