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Chemical Engineering :: Mass Transfer

  1. In a binary system, separation is very efficient, when the relative volatility is

  2. A.
    1
    B.
    > 1
    C.
    < 1
    D.
    0.5

  3. Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for

  4. A.
    constant molal overflow
    B.
    total reflux
    C.
    constant relative volatility
    D.
    all (a), (b) and (c)

  5. The binary diffusivity in gases does not depend upon the

  6. A.
    pressure
    B.
    temperature
    C.
    nature of the components
    D.
    none of these

  7. Berl saddle made of carbon cannot be used for

  8. A.
    alkalis
    B.
    SO2
    C.
    H2SO4
    D.
    oxidising atmosphere

  9. 1 kg of a saturated aqueous solution of a highly soluble component A at 60°C is cooled to 25°C. The solubility limits of A are (0.6 kgA/kg water) at 60°C and (0.2 kgA/kg water) at 25°C. The amount in kg of the crystals formed is

  10. A.
    0.4
    B.
    0.25
    C.
    0.2
    D.
    0.175

  11. During drying of a solid, the critical moisture content increases with

  12. A.
    decreased drying rate
    B.
    increased thickness of the solid
    C.
    increased drying rate
    D.
    both (b) and (c).

  13. Priming in a distillation column

  14. A.
    results from very low gas velocity.
    B.
    is desirable from point efficiency consideration.
    C.
    is characterised by the presence of foam throughout the space between trays.
    D.
    reduces the overall pressure drop.

  15. The commonly used solvent in supercritical extraction is

  16. A.
    methyl ethyl ketone.
    B.
    water.
    C.
    carbon tetrachloride.
    D.
    carbon dioxide.

  17. When the liquid over a plate is of uniform concentration, then

  18. A.
    Murphree efficiency > point efficiency.
    B.
    Murphree efficiency < point efficiency.
    C.
    Murphree efficiency = point efficiency.
    D.
    Murphree efficiency ≠ point efficiency.

  19. In saturated gas, the

  20. A.
    vapour is in equilibrium with the liquid at the gas temperature.
    B.
    vapour is in equilibrium with the liquid at the room temperature.
    C.
    partial pressure of vapour equals the vapour pressure of the liquid at room temperature.
    D.
    none of these.