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Chemical Engineering :: Mass Transfer

  1. Which of the following parameters remains constant during chemical dehumidifica-tion?

  2. A.
    Dry bulb temperature
    B.
    Partial pressure of vapour
    C.
    Wet bulb temperature
    D.
    None of these

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  3. Drying of a solid involves __________ transfer.

  4. A.
    only heat
    B.
    only mass
    C.
    both heat and mass
    D.
    none of these

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  5. Mechanism of moisture removal in case of freeze drying of food stuff is by

  6. A.
    evaporation
    B.
    sublimation
    C.
    dehydration
    D.
    adsorption

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  7. The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.

  8. A.
    composition
    B.
    temperature
    C.
    total pressure
    D.
    all (a), (b) and (c)

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  9. Which is not concerned directly with mass transfer ?

  10. A.
    Schmidt number
    B.
    Sherwood number
    C.
    Lewis relationship
    D.
    Froude number

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  11. Removal of __________ exemplifies an adsorption unit operation.

  12. A.
    uranium from its ore
    B.
    water from petrol
    C.
    ammonia from coke oven gas
    D.
    mustard oil from mustard seed

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  13. Can the efficiency of a plate in the distillation tower be greater than 100% ?

  14. A.
    Yes
    B.
    Normally not; but is possible if infinite number of plates are put.
    C.
    Never
    D.
    Yes ; if the reflux ratio is maximum.

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  15. With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________ , if the conduction and radiation through the solid are negligible.

  16. A.
    increases
    B.
    decreases
    C.
    remains same
    D.
    increases linearly

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  17. For gas absorption, low viscosity solvents are preferred, because of their

  18. A.
    better flow characteristics.
    B.
    low pumping pressure drop.
    C.
    rapid absorption rates.
    D.
    all (a), (b) and (c).

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  19. To remove all the moisture from a wet solid it requires exposure to __________ air.

  20. A.
    perfectly dry
    B.
    highly humid
    C.
    high temperature
    D.
    none of these

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