A. The binary diffusivity in liquids is of the order of 10-5 cm2/sec
B. Molecular diffusion in solid is much faster than that in liquids
C. Particles movement from higher concentration to lower concentration takes place in diffusion
process
D. According to Poiseuille’s law, the permeability decreases with increase in temperature for
flow of a gas through a given capillary
Related Mcqs:
- Pick out the wrong statement. Generally for physical adsorption, a gas of________________?
A. Higher molecular weight is adsorbed in preference to a gas of low molecular weight
B. High critical temperature is adsorbed in preference to a gas of low critical temperature
C. Low volatility is adsorbed in preference to a gas of high volatility
D. None of these - Pick out the wrong statement ?
A. Absorption factor is constant, when the equilibrium and operating lines are straight
B. In case of a stripper, the equilibrium curve is always below the operating line
C. In case of an absorber, the operating line is always above the equilibrium curve
D. In the absorption of low solubility gases, the liquid film is the controlling resistance - 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 - Pick out the wrong statement pertaining to the cooling towers ?
A. In case of induced draft cooling tower, the fan is placed at the top of the tower
B. Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and
hot discharged air
C. A natural draft cooling tower is recommended to be used, when the air humidity is low and air
temperature is also low
D. Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb
temperature - Pick out the wrong statement ?
A. A horizontal line on the humidity chart indicates the temperature changes at constant molal
humidity
B. When water is cooled from 80 to 70°C by exposure to the air with a wet bulb temperature of
60°C, then both the approach & the range would be 10°C
C. For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature
& adiabatic cooling lines are the same
D. Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either
reducing the mixture temperature or by increasing the total pressure - 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 - Pick out the wrong statement ?
A. Constant pressure distillation cannot separate an Azeotropic mixture
B. Relative volatility of a binary mixture changes appreciably with the minor change in
temperature
C. The relative volatility of a binary mixture at Azeotropic composition is unity
D. Flash distillation is practised on wide spread scale in petroleum refinery - Pick out the wrong statement ?
A. Different solids have different equilibrium moisture curves
B. Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele
method of theoretical plate calculation for distillation column
C. Heat removal load on cooler remains constant, even with increase of the reflux ratio in a
distillation column
D. Even a forced draft cooling tower cannot cool water below the wet bulb temperature - Pick out the wrong statement ?
A. Reboiler is not used in open steam distillation
B. The separation of solutes of different molecular sizes in a liquid solution by use of a suitable
membrane is called dialysis
C. Freeze drying is used for the drying of fish
D. Fenske-Underwood equation is used for calculating theoretical number of plates in a
distillation column at normal operating reflux condition - Pick out the wrong statement?
A. Critical moisture content is not a property of the material itself
B. A sharp increase in pressure drop gives an indication of the flooding in a distillation column
C. Separation of components is not possible in liquid extraction, if selectivity is unity
D. Dehydration of ethyl alcohol is most economically done by molecular distillation at very high
vacuum
