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Chemical Engineering :: Mass Transfer

  1. In a binary distillation column, if the feed contains 40 mole % vapour, the q line will have a slope of

  2. A.
    1.5
    B.
    -0.6
    C.
    -1.5
    D.
    0.6

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  3. Pick out the wrong statement.

  4. A.
    Mechanical agitation is required, if the system has low interfacial tension.
    B.
    Seive tray towers are generally used for systems having low interfacial tension.
    C.
    When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance.
    D.
    Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers.

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  5. Acetic acid will be most economically separated from a dilute solution of acetic acid in water by

  6. A.
    solvent extraction
    B.
    continuous distillation
    C.
    evaporation
    D.
    absorption

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  7. Design calculation for multiple component distillation is done by

  8. A.
    Ponchon-Savarit method
    B.
    Mccabe-Thiele method
    C.
    enthalpy concentration method
    D.
    tray to tray calculations.

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  9. To get high tray efficiency

  10. A.
    interfacial surface between liquid and gas phase should be large.
    B.
    time of contact between the two phases should be less.
    C.
    gas velocity should be very low.
    D.
    liquid entrainment should be severe.

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  11. The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is

  12. A.
    D/a
    B.
    D/2a
    C.
    proportional to D
    D.
    dependent on the Reynolds number

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  13. Pick out the wrong statement. Generally for physical adsorption, a gas of

  14. A.
    higher molecular weight is adsorbed in preference to a gas of low molecular weight.
    B.
    high critical temperature is adsorbed in preference to a gas of low critical temperature.
    C.
    low volatility is adsorbed in preference to a gas of high volatility.
    D.
    none of these.

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  15. In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in

  16. A.
    reducing the axial mixing.
    B.
    increasing the rate of extraction.
    C.
    maintaining the concentration difference between the two phases.
    D.
    all 'a', 'b' & 'c'.

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  17. In a vapor-liquid contacting equipment, the overall gas phase mass transfer co-efficient (M.T.C), KG is related to individual co-efficients (KG and KL) as

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