Practice Test: Question Set - 23
1. Moisture contained by a substance in excess of the equilibrium moisture is called the __________ moisture.
- (A) Unbound
- (B) Free
- (C) Critical
- (D) Bound
2. Which of the following is an undesirable characteristic for the solvent used in gas absorption?
- (A) Low vapor pressure
- (B) Low viscosity
- (C) High gas solubility
- (D) None of these
3. Hypersorption refers to a __________ process.
- (A) Fixed bed absorption
- (B) Moving bed absorption
- (C) Fixed bed adsorption
- (D) Moving
bed adsorption
4. Drying of refractory is normally carried out in a __________ dryer.
- (A) Open pan
- (B) Tray
- (C) Rotary vacuum
- (D) Truck/tunnel
5. For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will
- (A) Increase
- (B) Decrease
- (C) Remain same
- (D) Data insufficient,
can't be predicted
6. In case of liquids, the binary diffusivity is proportional to (where, T = temperature)
- (A) T
- (B) √T
- (C) T2
- (D) 1/T
7. A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?
- (A) The mixture exhibits
an azeotrope at 101.3 kPa
- (B) The composition of
the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10
- (C) The composition of
the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10
- (D) The mixture contain optical
isomers
8. The relative saturation of an unsaturated mixture of gas and vapor is independent of the
- (A) Nature of the vapor
- (B) Temperature of the
mixture
- (C) Composition of the
mixture
- (D) None of these
9. In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
- (A) Area between
operating line and 45° diagonal x-y diagram
- (B) Condenser and
reboiler surfaces
- (C) Tower cross-section
- (D) None of these
10. Advantage of continuous drying over batch drying is that the
- (A) Drying cost per unit
weight of dried product is less
- (B) Product with more
uniform moisture content is produced
- (C) Equipment size
required is smaller
- (D) All 'a', 'b' &
'c'
11. Which of the following assumes constant molal vaporization and overflow?
- (A) McCabe-Thiele method
- (B) Ponchan-Savarit
method
- (C) Enthalpy
concentration method
- (D) Plate absorption
column
12. An air-water vapor mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapor pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively. The humidity of air sample expressed as kg of water vapor/kg of dry air is:
- (A) 0.048
- (B) 0.079
- (C) 0.122
- (D) 0.152
13. Which of the following binary systems is an example of a maximum boiling azeotrope?
- (A) Water-hydrochloric
acid
- (B) Acetone-carbon
disulphide
- (C) Water-ethyl alcohol
- (D) n-heptane-n-octane
14. For an absorber, both equilibrium and operating line will be straight for
- (A) Concentrated solution
and non-isothermal operation
- (B) Dilute solution and
non-isothermal operation
- (C) Dilute solution and
isothermal operation
- (D) Concentrated solution
and isothermal operation
15. Channelling is most severe
- (A) In towers packed with
stacked packing
- (B) In towers packed
randomly with crushed solids
- (C) In dumped packing of
regular units
- (D) At very high liquid
flow rate
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