Mass Transfer

161.For _________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same.

  1. Unsaturated surface
  2. Constant rate
  3. Both (A) and (B)
  4. Neither (A) nor (B)

Correct answer: (C)
Both (A) and (B)

162.For a binary mixture distillation process, the degree of freedom is 2. However, if the pressure is fixed in this process, the number of independent variables in this process will be

  1. 1
  2. 0
  3. 2
  4. 3

Correct answer: (A)
1

163.For a binary mixture with low relative volatility,

  1. Use steam distillation
  2. Use molecular distillation
  3. Use high pressure distillation
  4. An azeotrope may be formed during distillation

Correct answer: (D)
Use high pressure distillation

164.For a binary mixture with low relative volatility, continuous rectification to get pure products will require

  1. Low reflux ratio
  2. Less number of trays
  3. Small cross-section column
  4. High reflux ratio

Correct answer: (D)
High reflux ratio

165.For a distillation column operating at minimum reflux, the

  1. Concentration of liquid and vapour leaving a plate will be same
  2. Reflux ratio will be maximum
  3. Number of plates required will be maximum
  4. None of these

Correct answer: (C)
Number of plates required will be maximum

166.For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams

  1. Increases
  2. Decreases
  3. Remain unaffected
  4. Passes through a maximum

Correct answer: (A)
Increases

167.For a single component absorber, the operating line is straight only when plotted in term of _________ units.

  1. Partial pressure
  2. Mole ratio
  3. Mole fraction
  4. None of these

Correct answer: (B)
Mole ratio

168.For a ternary mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a _________ of the equilateral triangular co-ordinates.

  1. Binary mixture is represented by the apex
  2. Binary mixture is represented by any point inside
  3. Ternary mixture is represented by the sides
  4. Pure component is represented by the apex

Correct answer: (D)
Pure component is represented by the apex

169.For absorbers, high pressure drop results in

  1. Increased efficiency
  2. Decreased efficiency
  3. High operating cost
  4. Better gas liquid contact

Correct answer: (C)
High operating cost

170.For absorbing a sparingly soluble gas in a liquid

  1. Gas side mass transfer co-efficient should be increased
  2. Liquid side mass transfer co-efficient should be increased
  3. Liquid side mass transfer co-efficient should be decreased
  4. Mass transfer co-efficient must be kept constant

Correct answer: (B)
Liquid side mass transfer co-efficient should be increased

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