According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the column ?

Related Mcqs:

1. Relative volatility varies with the concentration of component for an ideal solution. The relative volatility of a binary mixture may be defined as the ratio of vapor pressure of component ‘A’ to that of component ‘B’, when_________________?

   A. Only vapor phase follows Raoult’s law
   B. Only liquid phase obeys Dalton’s law
   C. Liquid phase obeys Dalton’s law and vapor phase obeys Raoult’s law
   D. Vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law

2. In a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raffinate phase R containing A at xB = 0.5 and xR = 0.05 respectively. The total mass of the extract phase is (in Kg) ?

   A. 6.89
   B. 8.89
   C. 10
   D. 8.25

3. The relative volatility of a binary mixture at constant temperature _________________ the total pressure?

   A. Decreases with increase in
   B. Increases with increase in
   C. Is independent of
   D. None of these

4. The relative volatility of a binary mixture at the Azeotropic composition is _______________________?

   A. 1
   B. > 1
   C. 0
   D. ∞

5. The-relative volatility for separation of a non-ideal binary mixture by distillation should be ___________________?

   A. 0
   B. 1
   C. > 1
   D. < 1

6. For a binary mixture with low relative volatility, continuous rectification to get pure products will require_____________________?

   A. Low reflux ratio
   B. Less number of trays
   C. Small cross-section column
   D. High reflux ratio

7. Relative volatility does not change appreciably with the change in_____________________?

   A. Temperature
   B. Vapour pressure of either component
   C. Total pressure
   D. None of these

8. An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) ____________________?

   A. Less number of trays are required
   B. Composition of the residue remains unchanged
   C. More number of trays are required but the residue composition remains unchanged
   D. More number of trays are required and the residue composition is more dilute in methanol

9. When the liquid phase and vapour phase of a binary system obeys Raoult’s and Dalton’s law respectively, the relative volatility is the ratio of________________________?

   A. Vapour pressure of component A to that of component B
   B. Vapour pressure of component A to the total pressure
   C. Vapour pressure of component A to the partial pressure of A
   D. Partial pressure of component A to the total pressure

10. With increase in pressure, the relative volatility for a binary system__________________?

    A. Increases
    B. Decreases
    C. Remains same
    D. Either A. or B., depends on the system