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Chemical Engineering :: Mass Transfer

  1. Which of the following is a suitable absorbent for removal of H2S from natural gas ?

  2. A.
    Vetrocoke solution
    B.
    Monoethanol amine (MEA)
    C.
    Dilute
    D.
    Hot water

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  3. Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are

  4. A.
    1
    B.
    8
    C.
    9
    D.
    10

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  5. Schimdt number and Lewis number for pure air at atmospheric conditions are respectively

  6. A.
    < 1 and ≈ 1
    B.
    1 and 0
    C.
    >1 and ≈ 1
    D.
    0 and ≈ 1

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  7. Below is given an equilibrium moisture curve of a substance. State which regions represent free moisture and unbound moisture respectively.

  8. A.
    II, III
    B.
    II, IV
    C.
    IV, III
    D.
    IV, II

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  9. Molecular diffusion is caused by the

  10. A.
    transfer of molecules from low concentration to high concentration region.
    B.
    thermal energy of the molecules.
    C.
    activation energy of the molecules.
    D.
    potential energy of the molecules.

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  11. At __________ reflux, theoretical number of plates in a distillation coloumn is calculated using Fenske-Underwood equation.

  12. A.
    operating
    B.
    total
    C.
    minimum
    D.
    maximum permissible

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  13. Separation of a mixture of two gases by absorption in the liquid solvent depends upon the difference in their

  14. A.
    viscosity
    B.
    density
    C.
    solubility
    D.
    relative volatility

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  15. Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation.

  16. A.
    molecular
    B.
    extractive
    C.
    steam
    D.
    simple

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  17. Which of the following equipments is not used in liquid-liquid extraction ?

  18. A.
    Pachuka tank
    B.
    Agitated vessels
    C.
    Centrifugal extractors
    D.
    Packed towers

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  19. Pick out the wrong statement.

  20. A.
    Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse.
    B.
    Packed towers are preferred over plate towers for handling corrosive and foamy liquids.
    C.
    Diameter of randomly packed tower is normally more than 1.2 metres.
    D.
    Due to uneven supply and improper distribution of liquid, problem of channeling, loading & flooding is generally encountered in packed towers.

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