Practice Test: Question Set - 16
1. In McCabe-Thiele method, at infinite reflux ratio
- (A) Number
of plates is maximum
- (B) Overhead product is
maximum
- (C) Both
the operating lines coincide with the diagram
- (D) None of these
2. Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the
- (A) Packing may be
crushed due to thermal expansion/contraction of the components of the
equipments
- (B) Pressure drop in the
equipment will be very high
- (C) Viscosity variation
of the fluids may cause channelling/flooding
- (D) None of these
3. Pick out the correct statement.
- (A) Higher
hold up of the solid in the rotary dryer results in better exposure of the
solids to the gas
- (B) The
'Hatta number' is important in problems involving gas absorption without
chemical reaction
- (C) For
a non-reacting binary mixture of ideal gases, the partial pressure distribution
of both components is linear in the case of steady state equimolal
counter-diffusion
- (D) Total reflux in case
of distillation operation requires infinite number of plates for a binary
system separation
4. A binary mixture of benzene and cyclohexane is separated by
- (A) Flash
vaporization
- (B) Extractive
distillation
- (C) Solvent
extraction
- (D) Ordinary
distillation
5. Mass transfer co-efficient 'K' according to penetration theory varies with mass diffusivity as
- (A) D0.5
- (B) D
- (C) 1/D
- (D) D1.5
6. Free flowing granular materials can be best dried in a __________ drier.
- (A) Rotary
- (B) Cylinder
- (C) Drum
- (D) Freeze
7. In a packed bed absorption column, the channelling will be noted by the
- (A) Increase in flow rate
- (B) Sharp drop in
pressure drop
- (C) Sharp rise in
pressure drop
- (D) None of these
8. The ratio of Murphree plate efficiency to point efficiency is always > 1 in a __________ flow model.
- (A) Plug
- (B) Perfectly mixed
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
9. Fractional solvent extraction
- (A) Employs only one
solvent
- (B) Employs two solvents
- (C) Results in low
interfacial tension
- (D) None of these
10. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower.
- (A) Is greater than
- (B) Is lower than
- (C) Is same as
- (D) Cannot be predicted
as data are insufficient
11. During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the __________ remains constant.
- (A) Wet bulb temperature
- (B) Partial pressure of
water vapor
- (C) Relative humidity
- (D) None of these
12. Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve.
- (A) 100
- (B) 50
- (C) 78
- (D) None of these
13. __________ is the separation technique used for desalination of sea water.
- (A) Thermal diffusion
- (B) Reverse osmosis
- (C) Adsorption
- (D) Absorption
14. The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an __________ law.
- (A) Exponential
- (B) Parabolic
- (C) Linear
- (D) Cubic
15. A distillation column separates 10000 kg/hr of a benzene-toluene mixture as shown in the figure below:
In the figure xF, xD and xW represent the weight fraction of benzene in the feed, distillate and residue respectively. The reflux ratio is
- (A) 0.5
- (B) 0.6
- (C) 1.0
- (D) 2.0