Chemical Engineering - Mass Exchange Between Phases MCQ - Set 38 - ObjectiveBooks

Chemical Engineering - Mass Exchange Between Phases MCQ - Set 38

Practice Test: Question Set - 38

1. Deaeration (removal of O2) of water is done by
    (A) Rectification
    (B) Absorption
    (C) Ion-exchange
    (D) Adsorption

2. For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because
    (A) Water has a high latent heat of evaporation
    (B) Lewis number is close to unity
    (C) They are always equal under all circumstances
    (D) Solubility of the components of air in water is very small

3. Dew point of a gas-vapor mixture
    (A) Increases with temperature rise
    (B) Decreases with temperature rise
    (C) Decreases with decrease in pressure
    (D) Increases with increase in pressure

4. If moisture content of solid on dry basis is X, then the same on wet basis is
    (A) X/(X + 1)
    (B) X/(1 - X)
    (C) (1 + X)/X
    (D) (1 - X)/X

5. __________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gas-vapor mixture.
    (A) Dry bulb
    (B) Wet bulb
    (C) Dew point
    (D) None of these

6. The-relative volatility for separation of a non-ideal binary mixture by distillation should be
    (A) 0
    (B) 1
    (C) > 1
    (D) < 1

7. In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapor, because
    (A) Temperature is less
    (B) Total pressure is less
    (C) Mixing of steam with the material being vaporized is not so intimate as to result in equilibrium condition
    (D) Saturated steam is used for steam distillation

8. Which of the following unit operations makes use of Thiele-Geddes equation?
    (A) Liquid-liquid extraction
    (B) Solid-liquid extraction
    (C) Multi-component absorption with chemical reaction
    (D) Multi-component distillation

9. Gaseous diffusion co-efficient increases with increase in the
    (A) Pressure
    (B) Temperature
    (C) Both (a) & (b)
    (D) Neither (a) nor (b)

10. Sides of equilateral-triangular co-ordinates (on which ternary liquid system is plotted) represent
    (A) A pure component
    (B) A binary mixture
    (C) A ternary mixture
    (D) Partially miscible ternary system

11. The rate of mass transfer is not dependent upon the
    (A) Degree of dispersion of one fluid in the other
    (B) Interfacial surface exposed between the phases
    (C) Both (a) & (b)
    (D) None of these

12. Air at a particular humidity is heated in a furnace. The new dew point
    (A) Decreases
    (B) Increases
    (C) Depends on the extent of heating
    (D) Remain unchanged

13. The rate of solid-liquid extraction is limited by the
    (A) Phase change of the solute as it dissolves in the solvent
    (B) Diffusion of the solute through the solvent in the pores to the outside of the particle
    (C) Diffusion of the solute from the solution in contact with the particle to the main bulk of the solution
    (D) All 'a', 'b' & 'c'

14. In case of gases, the binary diffusivity is proportional to (where, P = pressure).
    (A) P
    (B) 1/P
    (C) 1/√P
    (D) √P

15. One mole feed of a binary mixture of a given composition is flash vaporized at a fixed P and T. If Raoult's law is obeyed, then changing the feed composition would effect
    (A) The product composition but not the fraction vaporized
    (B) The product composition as well as the fraction vaporized
    (C) The fraction vaporized but not the product composition
    (D) Neither the product composition nor the fraction vaporized

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