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Chemical Engineering :: Mass Transfer

  1. Molecular seives are regenerated by heating to __________ °C.

  2. A.
    < 150
    B.
    200-330
    C.
    > 500
    D.
    > 1000

  3. In continuous distillation, the internal reflux ratio (Ri) and the external reflux ratio (Re) are related as

  4. A.
    B.
    C.
    Ri = Re
    D.

  5. In a counter-current extractor, as the axial mixing increases, the extraction efficiency

  6. A.
    increases
    B.
    decreases
    C.
    remains unchanged
    D.
    depends on the pressure of the system

  7. Heat sensitive materials like certain pharmaceuticals and food stuffs can be dried in a/an __________ dryer.

  8. A.
    indirect tray
    B.
    spray
    C.
    freeze
    D.
    none of these

  9. In extractive distillation, solvent is

  10. A.
    added to alter the relative volatility of the mixture.
    B.
    of high volatility.
    C.
    present in overhead stream.
    D.
    of high viscosity to give high tray efficiency.

  11. Radioactive nuclear waste is treated in

  12. A.
    mixer-settler extractor
    B.
    rotating-disc contactor
    C.
    pulsed column extractor
    D.
    Bollman extractor

  13. Large scale drying of sugar is done in a __________ dryer.

  14. A.
    spouted bed
    B.
    tray
    C.
    rotary
    D.
    truck

  15. __________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gas-vapor mixture.

  16. A.
    Dry bulb
    B.
    Wet bulb
    C.
    Dew point
    D.
    none of these

  17. The drying time between fixed moisture contents within the 'constant rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid )

  18. A.
    T
    B.
    T
    C.
    T1.5
    D.
    T3

  19. __________ equation applies to diffusivities in liquids.

  20. A.
    Gilliland
    B.
    Hirschfelder
    C.
    Wilke and Chang
    D.
    none of these