Q.1
Use of packed towers for distillation is generally limited to the
Q.2
A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process?
Q.3
The main reason for dividing a tall packed tower into series of small towers is to
Q.4
Which of the following parameters remains constant during chemical dehumidifica-tion?
Q.5
Which of the following is not a continuous drier?
Q.6
The relative saturation of an unsaturated mixture of gas and vapor is independent of the
Q.7
H₂S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H₂S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in metres) corresponding to an operating line given by, y = 5x + 0.001 is
Q.8
Which of the following plays an important role in problems of simultaneous heat and mass transfer?
Q.9
Rate of adsorption increases as the
Q.10
When the liquid over a plate is of uniform concentration, then
Q.11
Which of the following is the most commonly used leaching solvent in vegetable oil industry?
Q.12
Low viscosity absorbent is preferred for reasons of
Q.13
As the reflux ratio increases, the slope of the operating line for rectifying section
Q.14
Heat in BTU necessary to increase the temperature of 1 lb of gas and its accompanying vapour by 1°F is called the
Q.15
When a multistage tray tower uses a minimum reflux ratio, it implies
Q.16
In most of the vacuum crystalliser, vacuum is generally produced by means of a
Q.17
A minimum boiling azeotrope is exemplified by
Q.18
The individual mass transfer co-efficients (moles/m² . s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ?
Q.19
As the reflux ratio in a distillation coloumn is increased from the minimum, the
Q.20
In liquid extraction, if the selectivity is unity, then
Q.21
As the reflux ratio, in a continuous counter-current extraction is increased, the number of stages
Q.22
Drying operation under vacuum is carried out to
Q.23
Unit of molal diffusivity is
Q.24
Pick out the system with maximum boiling azeotrope at 1 atm.
Q.25
Leaching of uranium ore and gold ore is done in
Q.26
If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent.
Q.27
A binary mixture of benzene and cyclohexane is separated by
Q.28
When the feed to a distillation column is a saturated liquid, slope of the feed line is
Q.29
When the psychometric ratio is __________ then the adiabatic saturation temperature and wet bulb temperature becomes equal.
Q.30
Can a cooling tower cool water below the wet bulb temperature of inlet air?
Q.31
__________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gas-vapor mixture.
Q.32
In a counter-current liquid extractor
Q.33
Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are
Q.34
The fixed cost of a distillation column at minimum reflux ratio is
Q.35
The-relative volatility for separation of a non-ideal binary mixture by distillation should be
Q.36
For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams
Q.37
Raoult's law is applicable to the
Q.38
Pick out the system with minimum boiling azeotrope at 1 atm.
Q.39
Pick out the wrong statement.
Q.40
A good solvent used for absorption should not have very high
Q.41
Equilibrium-moisture curves of different solids
Q.42
In Mcabe-Thiele method, at infinite reflux ratio
Q.43
The operating cost of a distillation column at minimum reflux ratio is
Q.44
Sodium bicarbonate is produced during soda ash manufacture using a __________ tower.
Q.45
In which of the following unit operations, the selectivity is an important parameter?
Q.46
Perforated plate towers are unique for solvent extraction because, they provide
Q.47
Paper industry employs __________ driers.
Q.48
With increase in temperature, the mutual solubility of two liquids
Q.49
The binary diffusivity in gases at atmospheric conditions is about
Q.50
To get high tray efficiency
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