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Chemical Engineering :: Mass Transfer

  1. Dimension of mass diffusivity is the same as that of

  2. A.
    kinematic viscosity
    B.
    dynamic viscosity
    C.
    surface tension
    D.
    pressure

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  3. Dorr thickener is an equipment used for

  4. A.
    classification
    B.
    sedimentation
    C.
    clarification
    D.
    leaching

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  5. Steam distillation is used to separate

  6. A.
    azeotropes.
    B.
    high boiling substances from nonvolatile impurities.
    C.
    heat sensitive materials.
    D.
    mixtures of low relative volatility.

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  7. In distillation where q is defined as the moles of liquid flow in the stripping section per mole of feed introduced, for saturated liquid feed

  8. A.
    q > 1
    B.
    q < 1
    C.
    q = 1
    D.
    q = 0

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  9. Which of the following is an undesirable property in a tower packing ?

  10. A.
    Large surface per unit volume.
    B.
    Large free cross-section.
    C.
    Low weight per unit volume.
    D.
    Large weight of liquid retained.

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  11. Water entrained by circulating air in cooling towers is termed as

  12. A.
    drift
    B.
    blow down
    C.
    vapor load
    D.
    none of these.

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  13. A 25 cm x 25 cm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m x 1m x 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is

  14. A.
    1000
    B.
    1500
    C.
    2000
    D.
    2500

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  15. With increase in temperature, the rate of leaching increases, because the

  16. A.
    diffusivity of solute increases.
    B.
    viscosity of solvent decreases.
    C.
    thermal conductivity of solute increases.
    D.
    none of these.

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  17. Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in terms of __________ humidity.

  18. A.
    molal
    B.
    relative
    C.
    percentage
    D.
    none of these

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  19. The Kundsen diffusivity is proportional to (where, T = absolute temperature)

  20. A.
    T
    B.
    T2
    C.
    T
    D.
    T4

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