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Chemical Engineering :: Mass Transfer

  1. Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number.

  2. A.
    Sherwood
    B.
    Schmidt
    C.
    Peclet
    D.
    Stanton

  3. If the specific heats of a gas and a vapor are 0.2KJ/Kg.°K and 1.5 KJ/Kg.°K respectively, and the humidity is 0.01; the humid heat in KJ/°Kg. is

  4. A.
    0.31
    B.
    0.107
    C.
    0.017
    D.
    0.215

  5. Liquid diffusivity is of the order of __________ cm2 /second.

  6. A.
    0.01
    B.
    0.1
    C.
    10-5 to 10-6
    D.
    > 1

  7. The solvent used in liquid extraction should not have high latent heat of vaporisation, because

  8. A.
    the pressure drop and hence the pumping cost will be very high.
    B.
    it cannot be recovered by distillation.
    C.
    its recovery cost by distillation may be prohibitatively high.
    D.
    it will decompose while recovering by distillation.

  9. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower.

  10. A.
    is greater than
    B.
    is lower than
    C.
    is same as
    D.
    cannot be predicted as data are insufficient

  11. Molarity is defined as the number of gm moles of solute per __________ of solvent.

  12. A.
    litre
    B.
    kg
    C.
    gm
    D.
    c.c

  13. The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around

  14. A.
    1
    B.
    0.24
    C.
    3.97
    D.
    600

  15. Which of the following T-H diagram is valid for dehumidification operation ?


  16. 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)

  17. 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.

  18. The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an __________ law.

  19. A.
    exponential
    B.
    parabolic
    C.
    linear
    D.
    cubic