Mass Transfer

541.Weeping in a distillation column

  1. Increases tray efficiency
  2. Provides large interfacial surface for mass transfer
  3. Results due to very high gas velocity
  4. Results due to very low gas velocity

Correct answer: (D)
Results due to very low gas velocity

542.Weight of 1 m3 of humid air as compared to 1 m3 of dry air, under the same conditions, is

  1. Less
  2. More
  3. Same
  4. Unpredictable

Correct answer: (A)
Less

543.Wet bulb and dry bulb temperatures becomes identical at _________ percent saturation curve.

  1. 100
  2. 50
  3. 78
  4. None of these

Correct answer: (A)
100

544.Wetted wall tower experiment determines the

  1. Molal diffusivity
  2. Volumetric co-efficient
  3. Mass transfer co-efficient
  4. None of these

Correct answer: (C)
Mass transfer co-efficient

545.What is the degree of freedom of an absorption process in which only one component is transferred between phases?

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

Correct answer: (C)
3

546.What is the reflux ratio at total reflux?

  1. Zero
  2. Infinity
  3. Unity
  4. Data insufficient

Correct answer: (B)
Infinity

547.When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30°C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,

  1. As the acetone concentration increases, the solubility curves approach each other
  2. Both the phases become identical at a particular common point on both the solubility curves called the plait point
  3. The distribution curve which is a plot between x (acetone concentration in one phase) and y (acetone concentration in other phase) is analogous to x-y curve used in distillation and absorption terminates on the x = y diagonal at the concentration of the plait point
  4. All (A), (B) and (C)

Correct answer: (D)
All (A), (B) and (C)

548.When adsorption hysteresis is observed, the desorption equilibrium pressure is _________ that obtained by adsorption.

  1. Always lower than
  2. Always higher than
  3. Same as
  4. Dependent on the system; can be either lower or higher than

Correct answer: (A)
Always lower than

549.When an unsaturated air-water mixture is heated at constant pressure, then

  1. The partial pressure of water vapour increases
  2. The specific humidity decreases
  3. The relative humidity increases
  4. The relative humidity decreases

Correct answer: (D)
The relative humidity decreases

550.With the lowering of equilibrium pressure, at a given temperature, the amount of adsorbate on the adsorbent

  1. Increases
  2. Decreases
  3. Remain same
  4. Either (A) or (B), depends on the system

Correct answer: (b)
Decreases

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