Practice Test: Question Set - 05
1. For stripping of a gas in a counter current stripper, the operating line
- (A) Lies above the
equilibrium curve
- (B) Lies below the
equilibrium curve
- (C) Can lie above or
below the equilibrium curve
- (D) Is always parallel to
the equilibrium curve
2. The Reynolds number of the liquid was increased 100 fold for a laminar falling film used for gas-liquid contacting. Assuming penetrating theory is applicable, the fold increase in the mass transfer co-efficient (Kc) for the same system is.
- (A) 100
- (B) 10
- (C) 5
- (D) 1
3. The boiling points of pure components of a binary system __________ with increase in total pressure of the system.
- (A) Decreases
- (B) Increases
- (C) Remains unchanged
- (D) May increase or
decrease, depends on the system
4. In gas-liquid contact operation, the number of ideal stages, N = (xa - xb)/(xb - x*b). This is true when the stripping factor 'S' is
- (A) S > 1
- (B) S < 1
- (C) S = 1
- (D) S = ∞
5. Large scale usage of flash distillation is practiced in
- (A) Soap manufacturing
- (B) Ammonia synthesis
plant
- (C) Polymerization
industry
- (D) Petroleum refining
6. Drying of a solid involves __________ transfer.
- (A) Only heat
- (B) Only mass
- (C) Both heat and mass
- (D) None of these
7. Desulphurisation of petrol is done in a
- (A) Bollman extractor
- (B) Rotating disc
extractor
- (C) Packed extraction
column
- (D) Plate type extraction
column
8. Pick out the wrong statement
- (A) Co-current absorbers
are usually used, when the gas to be dissolved in the liquid is a pure
substance
- (B) In
case of gas absorption, HETP is equal to HTU, when both the operating line
& the equilibrium lines are parallel
- (C) Hatta number is
important in case of gas absorption with chemical reaction
- (D) In actual practice,
absorption is an endothermic process, while stripping is an exothermic process
9. Which of the following increases during evaporative cooling process with recirculated water supply?
- (A) Wet bulb temperature
- (B) Relative humidity
- (C) Partial pressure of
vapor
- (D) Both (b) and (c)
10. Operating velocity in a packed tower is usually __________ the flooding velocity.
- (A) Half
- (B) Twice
- (C) Equal to
- (D) More than
11. For gas absorption, low viscosity solvents are preferred, because of their
- (A) Better flow
characteristics
- (B) Low pumping pressure
drop
- (C) Rapid absorption
rates
- (D) All (a), (b) and (c)
12. Which of the following is used for the concentration of rubber latex?
- (A) Agitated film
evaporator
- (B) Long tube vertical
evaporator
- (C) Short tube evaporator
- (D) Calandria
13. Pressure drop through plate tower as compared to that through packed tower, for the same duty will be
- (A) Less
- (B) More
- (C) Equal
- (D) Either (a) or (b);
depends on the packing height
14. In case of absorption & stripping, the interface of the liquid & gas phases are present in equilibrium, when the diffusional resistance of __________ is zero.
- (A) Interface
- (B) Gas phase
- (C) Liquid phase
- (D) All 'a', 'b' &
'c'
15. Henry's law states that the
- (A) Partial pressure of a
component over a solution is proportional to its mole fraction in the liquid
- (B) Partial
pressure of a component over a solution is proportional to the mole fraction in
the vapour
- (C) Vapor pressure is
equal to the product of the mole fraction and total pressure
- (D) Partial pressure is
equal to the product of the mole fraction and total pressure
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