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Chemical Engineering :: Mass Transfer

  1. As per Gilliland's equation, the diffusivity is

  2. A.
    directly proportional to 'T1.5'.
    B.
    inversely proportional to 'P'.
    C.
    dependent on the molecular volume & molecular weight of components.
    D.
    all 'a', 'b' & 'c'.

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  3. Pick out the wrong statement.

  4. A.
    When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the equilibrium curve.
    B.
    The average distance between the operating line and equilibrium line is large, when the liquid-gas ratio is also large in case of a counter current gas absorption tower.
    C.
    The operating line lies above the equilibrium curve in case of a gas desorber.
    D.
    With decrease in the liquid flow rate for a fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process.

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  5. A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.

  6. A.
    21.7
    B.
    20
    C.
    27.3
    D.
    18.7

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  7. Which of the following is not fixed by the process requirements, in the design of absorbers ?

  8. A.
    Flow rate of the entering gas.
    B.
    Composition of the entering liquid.
    C.
    Terminal concentrations of gas stream.
    D.
    None of these.

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  9. If the amount of the steam used in steam distillation is increased, the temperature of distillation

  10. A.
    increases
    B.
    decreases
    C.
    remains unchanged
    D.
    depends on relative volatility

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  11. Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture.

  12. A.
    unbound
    B.
    critical
    C.
    free
    D.
    bound

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  13. Inside the distillation columns, the

  14. A.
    highest temperatures is near the feed plate.
    B.
    driving force for the liquid flow is its weight.
    C.
    vapors are not always at their dew points.
    D.
    all (a), (b) and (c)

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  15. When the psychometric ratio is __________ then the adiabatic saturation temperature and wet bulb temperature becomes equal.

  16. A.
    1
    B.
    < 1
    C.
    > 1
    D.

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  17. Desirable value of absorption factor in an absorber is

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

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  19. Refractory bricks are usually dried in a __________ dryer.

  20. A.
    tray
    B.
    tunnel
    C.
    conveyor
    D.
    festoon

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