MCQ Test Questions Mass Transfer - Chemical Engineering - Set 32 - ObjectiveBooks

MCQ Test Questions Mass Transfer - Chemical Engineering - Set 32

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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