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Chemical Engineering :: Mass Transfer

  1. For continuous drying of grannular or crystalline material, the dryer used is the __________ dryer.

  2. A.
    tunnel
    B.
    tray
    C.
    rotary
    D.
    none of these

  3. When adsorption hysteresis is observed, the desorption equilibrium pressure is __________ that obtained by adsorption.

  4. A.
    always lower than
    B.
    always higher than
    C.
    same as
    D.
    dependent on the system; can be either lower or higher than

  5. Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the __________ moisture.

  6. A.
    bound
    B.
    unbound
    C.
    critical
    D.
    none of these

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

  8. A.
    low reflux ratio
    B.
    less number of trays
    C.
    small cross-section column
    D.
    high reflux ratio

  9. The efficiency of a plate column will be maximum, when the flow is ideal __________ the plate.

  10. A.
    across
    B.
    above
    C.
    both (a) & (b)
    D.
    neither (a) nor (b)

  11. Heat load in a cooling tower

  12. A.
    means the amount of heat thrown away (KCal/hr.) by the cooling tower.
    B.
    is equal to the number of kg, of water circulated times the cooling range.
    C.
    both (a) & (b).
    D.
    neither (a) nor (b).

  13. In case of absorption with exothermic reaction, for fluids having

  14. A.
    Pr = Sc; percentage change in heat and mass transfer flux will be the same for a given change in the degree of turbulence.
    B.
    Pr = Sc = 1; total mass, momentum and thermal diffusivity will be the same.
    C.
    both (a) and (b)
    D.
    Pr = Sc ; there won't be any change in heat and mass transfer flux with changes in degree of turbulence.

  15. Detergent solution is dried to a powder in a

  16. A.
    spray dryer
    B.
    spouted bed dryer
    C.
    tunnel dryer
    D.
    pan open to atmosphere

  17. Which of the following mixtures does not form an azeotrope at atmosheric pressure?

  18. A.
    Water-alcohol
    B.
    Methyl alcohol-acetone
    C.
    Butyl acetate-water
    D.
    None of these

  19. During bottling of cold drinks (e.g. Pepsi), the main resistance to mass transfer for the absorption of carbon dioxide in water lies in the

  20. A.
    gas film
    B.
    liquid film
    C.
    liquid-gas interface
    D.
    none of these