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Home Chemical Engineering Mass Transfer Comments

  • Question
  • As the reflux ratio in a distillation coloumn is increased from the minimum, the


  • Options
  • A. slope of the operating line in stripping section decreases.
  • B. number of plates decreases very slowly first and then more and more rapidly.
  • C. total cost first decreases and then increases.
  • D. liquid flow increases while the vapor flow decreases for a system.

  • Correct Answer
  • total cost first decreases and then increases. 


  • Mass Transfer problems


    Search Results


    • 1. The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is

    • Options
    • A. natural draft cooling tower
    • B. induced draft cooling tower
    • C. spray chamber
    • D. none of these
    • Discuss
    • 2. Which of the following unit operations makes use of Thiele-Geddes equation?

    • Options
    • A. Liquid-liquid extraction
    • B. Solid-liquid extraction
    • C. Multicomponent absorption with chemical reaction
    • D. Multicomponent distillation.
    • Discuss
    • 3. Overall efficiency of the distillation column is

    • Options
    • A. the ratio of number of ideal plates to actual plates.
    • B. the ratio of number of actual plates to ideal plates.
    • C. same as the Murphree efficiency.
    • D. always more than the point efficiency.
    • Discuss
    • 4. In batch distillation with constant reflux, overhead product composition __________ with time.

    • Options
    • A. increases
    • B. decreases
    • C. does not vary
    • D. may increase on decrease, depends on the system.
    • Discuss
    • 5. With increase in pressure, the relative volatility for a binary system

    • Options
    • A. increases.
    • B. decreases.
    • C. remains same.
    • D. either (a) or (b), depends on the system.
    • Discuss
    • 6. Total reflux in a distillation operation requires minimum

    • Options
    • A. reboiler load
    • B. number of plates
    • C. condenser load
    • D. all (a), (b) and (c)
    • Discuss
    • 7. Which of the following remains constant during sensible cooling process?

    • Options
    • A. Specific humidity
    • B. Partial pressure of vapour
    • C. Both (a) and (b)
    • D. Neither (a) nor (b)
    • Discuss
    • 8. Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a

    • Options
    • A. higher dew point.
    • B. higher absolute (specific) humidity.
    • C. higher relative humidity
    • D. higher wet bulb temperature.
    • Discuss
    • 9. Dew point of a gas-vapour mixture

    • Options
    • A. increases with temperature rise.
    • B. decreases with temperature rise.
    • C. decreases with decrease in pressure.
    • D. increases with increase in pressure.
    • Discuss
    • 10. To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)

    • Options
    • A. increase both 'G' and 'S'.
    • B. decrease both 'G' and 'S'.
    • C. increase 'S' and decrease 'G'.
    • D. increase 'G' and decrease 'S'
    • Discuss


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