Practice Test: Question Set - 14
1. All moisture in a non-hygroscopic material is the __________ moisture.
- (A) Free
- (B) Equilibrium
- (C) Unbound
- (D) Bound
2. Molecular diffusivity of a liquid
- (A) Increases
with temperature
- (B) Decreases
with temperature
- (C) May
increase or decrease with temperature
- (D) Is
independent of temperature
3. Raschig ring made of porcelain cannot be used for treating concentrated
- (A) Hydrochloric
acid
- (B) Nitric acid
- (C) Alkalis
- (D) Sulphuric
acid
4. Use of natural draft cooling tower is practiced, when the air has low
- (A) Humidity
- (B) Temperature
- (C) Both 'a' & 'b'
- (D) Neither 'a' nor 'b'
5. At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapor free gas is __________ percent.
- (A) 100
- (B) 0
- (C) 50
- (D) Between
0 and 100
6. Tower diameter may be decreased by
- (A) Using higher reflux
ratio
- (B) Use of increased tray
spacing
- (C) Increasing the liquid
flow rate
- (D) Increasing the vapor
flow rate
7. Pick out the wrong statement.
- (A) The mass diffusivity,
the thermal diffusivity and the eddy momentum diffusivity are the same
for NSc = NPr= 1
- (B) 1 Nm3 of
dry air is lighter than 1Nm3 of humid air
- (C) The Lewis number of a
mixture is unity, when the thermal diffusivity is equal to the mass diffusivity
- (D) An Azeotropic mixture
of two liquids has boiling point higher than either of them, when it shows
negative deviation from Raoult's Law
8. The humid volume may be increased by increasing the
- (A) Temperature at
constant humidity
- (B) Humidity at constant
temperature
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
9. Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.)
- (A) (1 + Ro)
= Ro/Ri
- (B) (1 - Ro)
= Ro/Ri
- (C) (1 + Ri)
= Ro/Ri
- (D) (1 - Ri)
= Ro/Ri
10. According to Poiseuille's law, the permeability for gas flow through a capillary is proportional to (where, μ = gas viscosity)
- (A) μ
- (B) 1/μ
- (C) √μ
- (D) μ2
11. Even though bubble cap towers are very effective for humidification operation, they are not used commonly in industries, because of the
- (A) High evaporation
losses of water
- (B) High pressure drop of
the gas
- (C) Difficulty in its
fabrication
- (D) None of these
12. In case of constant underflow extraction operation, the __________ at all solute concentration.
- (A) Solids are drained to
the same extent
- (B) Ratio of the
insoluble to solution is constant
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
13. Which of the following has the same dimension as mass diffusivity?
- (A) Momentum flux
- (B) Kinematic viscosity
- (C) Thermal diffusivity
- (D) Both (b) and (c)
14. Packed column distillation is limited to the column __________ meters.
- (A) Height < 6
- (B) Diameter < 0.6
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
15. Which of the following decreases during evaporative cooling process with recirculated water supply?
- (A) Wet bulb temperature
- (B) Relative humidity
- (C) Partial pressure of
vapor
- (D) None of these
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