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This set of Mass Transfer Multiple Choice Questions & Answers (MCQs) focuses on Mass Transfer Set 19

Q1 | As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches
  • That of normal condensation
  • Integral heat of adsorption
  • Zero
  • None of these
Q2 | During bottling of cold drinks (e.g. Pepsi), the main resistance to mass transfer for the absorption of carbon dioxide in water lies in the
  • Gas film
  • Liquid film
  • Liquid-gas interface
  • None of these
Q3 | Relative humidity is the ratio of the
  • Partial pressure of the vapour to the vapour pressure of the liquid at room temperature
  • Partial pressure of the vapour to the vapour pressure of the liquid at gas temperature
  • Actual humidity to saturation humidity
  • None of these
Q4 | In the absorption of ammonia in water, the main resistance to absorption is by the__________ phase.
  • Liquid
  • Gas
  • Both (A) & (B)
  • Neither (A) nor (B)
Q5 | In paper industry, paper is dried in a __________ dryer.
  • Tunnel
  • Heated cylinder
  • Conveyor
  • Festoon
Q6 | Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around __________ inches.
  • 5
  • 30
  • 60
  • 100
Q7 | Which of the following plays an important role in problems of simultaneous heat and mass transfer?
  • Lewis number
  • Schmidt number
  • Prandtl number
  • Sherwood number
Q8 | In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter
  • > 4 :1
  • < 8 : 1
  • > 8:1
  • < 6:1
Q9 | If f = moles of vapour present per mole of feed, then the slope of feed line is (McCabeThiele method)
  • (1 - f)/f
  • #NAME?
  • #NAME?
  • #NAME?
Q10 | Pick out the wrong statement.
  • The operating line always lies above the equilibrium solubility curve in case of a single component absorber
  • The operating line always lies below the equilibrium solubility curve in case of a single component stripper
  • The operating pressure in solvent extraction system should be below vapor pressures of all components
  • The solubility of a particular gas in ideal solution in any solvent is always the same
Q11 | Mass transfer co-efficient of liquid is
  • Affected more by temperature than that for gases
  • Affected much less by temperature than that for gases
  • Not affected by the temperature
  • None of these
Q12 | Heat sensitive materials with very high latent heat of vaporisation may be economically separated using
  • Liquid extraction
  • Distillation
  • Evaporation
  • Absorption
Q13 | The reciprocal of stripping factor is termed as
  • Selectivity index
  • Relative volatility
  • Absorption factor
  • Murphree efficiency
Q14 | 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,
  • Composition of vapors and that of liquid do not vary throughout the column
  • Reboiler load and condenser load are minimum
  • The top and bottom compositions are unchanged with and without total reflux
  • The top and bottom compositions correspond to the maximum enrichment available
Q15 | In distillation columns, the number of bubble caps per tray primarily depends upon the
  • Allowable liquid velocity
  • Allowable gas velocity
  • Allowable gas and liquid velocities
  • Feed composition
Q16 | Batch tray dryers suffers from the disadvantage of
  • High maintenance cost
  • Non-uniform & low production rate
  • High labour cost & low heat economy
  • All 'a', 'b' & 'c'
Q17 | For absorbing a sparingly soluble gas in a liquid
  • Gas side mass transfer co-efficient should be increased
  • Liquid side mass transfer co-efficient should be increased
  • Liquid side mass transfer co-efficient should be decreased
  • Mass tr
Q18 | Smoke is an example of
  • Solid dispersed in liquid
  • Solid dispersed in gas
  • Liquid dispersed in gas
  • Gas dispersed in liquid
Q19 | Low viscosity absorbent is preferred for reasons of
  • Rapid absorption rates and good heat transfer characteristics
  • Improved flooding characteristics
  • Low pressure drop on pumping
  • All (A), (B) and (C)
Q20 | Pick out the wrong statement.
  • Cellulose acetate membranes are used in dialysis process
  • Elutriation process refers to when the soluble material is largely concentrated on the surface of an insoluble solid and is simply washed off by the solvent
  • 'Cascade' means a group of stages interconnected so that various streams flow from one to another
  • Zirconia probe is used for the humidity measurement
Q21 | The wetted wall tower is used to determine
  • Individual mass transfer co-efficient (M.T.C.) in gaseous system
  • M.T.C. of individual components in a liquid-liquid system
  • M.T.C. of liquid in liquid-gas system
  • The overall M.T.C. of the system
Q22 | Rotary dryers cannot handle __________ materials.
  • Free flowing
  • Dry
  • Sticky
  • Granular
Q23 | In a solution containing 0.30 Kg mole of solute and 600 kg of solvent, the molality is
  • 0.5
  • 0.6
  • 1
  • 2
Q24 | Small dia distillation column can be a
  • Packed column
  • Sieve tray
  • Bubble cap
  • Any of these
Q25 | Prandtl number for water at 20°C is about
  • 7
  • 70
  • 0.7
  • 150