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Chemical Engineering :: Mass Transfer

  1. Raschig ring made of procelain cannot be used for treating concentrated

  2. A.
    hydrochloric acid
    B.
    nitric acid
    C.
    alkalis
    D.
    sulphuric acid

  3. H2S present in naphtha reformed gas is removed by absorbing with

  4. A.
    ethanolamine
    B.
    K2CO3
    C.
    HCl
    D.
    vacuum gas oil

  5. During constant rate drying period, vaporisation rate per unit drying surface area

  6. A.
    decreases with time.
    B.
    increases with time.
    C.
    does not change with time,
    D.
    does not affect the moisture content of the wet solid.

  7. Pick out the wrong statement.

  8. A.
    Mass transfer co-efficient does not account for gase-liquid diffusion.
    B.
    Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer operation.
    C.
    Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process.
    D.
    Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process.

  9. In rectifying section of a continuous distillation column, the

  10. A.
    vapour is enriched with low boilers.
    B.
    vapour is enriched with high boilers.
    C.
    liquid is stripped of high boilers.
    D.
    none of these.

  11. For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams

  12. A.
    increases
    B.
    decreases
    C.
    remains unaffected
    D.
    passes through a maximum

  13. According to Chilton-Colburn analogy for mass transfer, NSt.NSc2/3 is equal to

  14. A.
    f
    B.
    f/2
    C.
    2f
    D.
    1/f

  15. A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is

  16. A.
    0.54
    B.
    1.04
    C.
    1.24
    D.
    1.94

  17. Minimum reflux ratio in a distillation column results in

  18. A.
    optimum number of trays.
    B.
    minimum reboiler size.
    C.
    maximum condenser size.
    D.
    minimum number of trays.

  19. Flooding in a distillation column is detected by a sharp

  20. A.
    increase in Murphree plate efficiency.
    B.
    decrease in pressure drop.
    C.
    decrease in liquid hold up in the coloumn.
    D.
    increase in pressure drop.