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Chemical Engineering :: Mass Transfer

  1. Can a cooling tower cool water below the wet bulb temperature of inlet air ?

  2. A.
    yes
    B.
    no
    C.
    yes ; but height of cooling tower will be prohibitively high.
    D.
    yes ; but the air flow rate should be excessively high.

  3. The solvent used in liquid-liquid extraction should have __________ less than one.

  4. A.
    selectivity
    B.
    distribution co-efficient
    C.
    both (a) and (b)
    D.
    neither (a) nor (b).

  5. The suitable evaporator for concentration of foaming liquids is a __________ evaporator.

  6. A.
    long tube
    B.
    short tube
    C.
    vacuum
    D.
    falling film

  7. The ratio of Murphree plate efficiency to point efficiency is always > 1 in a __________ flow model.

  8. A.
    plug
    B.
    perfectly mixed
    C.
    both (a) & (b)
    D.
    neither (a) nor (b)

  9. Tea percolation employs

  10. A.
    liquid-liquid extraction
    B.
    leaching
    C.
    absorption
    D.
    none of these

  11. Which of the following assumes constant molal vaporisation and overflow ?

  12. A.
    McCabe-Thiele method
    B.
    Ponchan-Savarit method
    C.
    Enthalpy concentration method
    D.
    Plate absorption column

  13. Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be

  14. A.
    1
    B.
    > 1
    C.
    < 1
    D.
    ≤ 1

  15. Pick out the wrong statement pertaining to leaching.

  16. A.
    Fine solids can not be leached in a Pachuka tank.
    B.
    Door classifier can be used for leaching of coarse solids.
    C.
    Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor.
    D.
    Very high temperature is not needed for the leaching of sugar beet.

  17. Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve.

  18. A.
    100
    B.
    50
    C.
    78
    D.
    none of these

  19. NSc/NPr is called the

  20. A.
    psychrometric ratio
    B.
    Lewis number
    C.
    Sherwood number
    D.
    Stantan number