Chemical Engineering - Mass Transfer in Laminar Flow Questions - Set 40 - ObjectiveBooks

Chemical Engineering - Mass Transfer in Laminar Flow Questions - Set 40

Practice Test: Question Set - 40


1. When the feed to a distillation column is a saturated liquid, slope of the feed line is
    (A) Zero
    (B) Unity
    (C) Infinity
    (D) None of these

2. The absorption factor is defined as (where, L = liquid flow rate, G = gas flow rate and, m = slope of the equilibrium line).
    (A) L/mG
    (B) G/mL
    (C) mL/G
    (D) LG/m

3. Chemisorption (chemical adsorption) is
    (A) Same as "Van der Waals" adsorption
    (B) Characterized by adsorption of heat
    (C) An irreversible phenomenon
    (D) A reversible phenomenon

4. A mixture of 10% C6H6 vapor in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.
    (A) 21.7
    (B) 20
    (C) 27.3
    (D) 18.7

5. Inside the distillation column, the
    (A) Driving force for the vapor flow is the pressure drop
    (B) Liquids are not always at their bubble points
    (C) Pressure increases gradually from bottom to the top of the column
    (D) None of these

6. Dry bulb temperature of unsaturated air is more than its __________ temperature.
    (A) Dew point
    (B) Wet bulb
    (C) Both 'a' & 'b'
    (D) Neither 'a' nor 'b'

7. Boiling point diagram is not affected by the ambient
    (A) Pressure
    (B) Humidity
    (C) Temperature
    (D) Both (b) and (c)

8. Total reflux in a distillation operation requires minimum
    (A) Reboiler load
    (B) Number of plates
    (C) Condenser load
    (D) All (a), (b) and (c)

9. Inside the distillation columns, the
    (A) Highest temperatures is near the feed plate
    (B) Driving force for the liquid flow is its weight
    (C) Vapors are not always at their dew points
    (D) All (a), (b) and (c)

10. An Azeotropic mixture is a __________ mixture.
    (A) Binary
    (B) Ternary
    (C) Constant boiling point
    (D) None of these

11. The change in enthalpy per unit weight of adsorbed gas when adsorbed on gas free or "outgassed" adsorbent to from a definite concentration of adsorbate is called its
    (A) Integral heat of adsorption
    (B) Heat of wetting
    (C) Differential heat of adsorption
    (D) Heat of normal condensation

12. The diffusivity (D) in a binary gas mixture is related to the temperature (T) as
    (A) D  T
    (B) D  T0.5
    (C) D  T1.5
    (D) D  T2

13. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = __________
    (A) 1
    (B) 0.5
    (C) 10
    (D) 0

14. At a fixed total pressure, humidity depends only on the
    (A) Partial pressure of vapor in the mixture
    (B) Heat capacity of the vapor
    (C) Density of the vapor
    (D) None of these

15. In extractive distillation, solvent is
    (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

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