A. Mass transfer co-efficient does not account for gas-liquid diffusion
B. Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer
operation
C. Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process
D. Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process
Related Mcqs:
- 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. Mechanical agitation is required, if the system has low interfacial tension
B. Sieve tray towers are generally used for systems having low interfacial tension
C. When Henry’s law constant is very small, then the mass transfer rate is controlled by the gas
film resistance
D. Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar
and turbulent layers - Pick out the wrong statement pertaining to the rotary dryer ?
A. Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it
down through the current of hot air/gases. It extends from the wall to a distance which is about
8-12% of the inside diameter of shell
B. Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at
any instant. The best performance for rotary drier is obtained, when the hold up is in the range
of 0.05 to 0.15
C. Rotary dryer is suitable for drying sticky material
D. Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute - Pick out the wrong statement ?
A. With decrease in feed temperature, the number of plates required for binary distillation
decreases for a given ‘L/V’ ratio
B. The extraction per unit of total height for a short packed column is more effective than for a
tall column, in case of liquid-liquid extraction
C. Natural draft cooling towers are made of ferroconcrete and its cross-section is wider at the
bottom
D. Vander wall adsorption is also called chemisorption - Pick out the wrong statement pertaining to leaching ?
A. Fine solids cannot be leached in a Pachuca tank
B. Door classifier can be used for leaching of coarse solids
C. Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor
D. Very high temperature is not needed for the leaching of sugar beet - 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. When the concentration difference for the mass transfer becomes zero at the bottom of the gas
absorption tower, then the upper end of the operating line touches the equilibrium curve
B. The average distance between the operating line and equilibrium line is large, when the liquidgas
ratio is also large in case of a counter current gas absorption tower
C. The operating line lies above the equilibrium curve in case of a gas desorber
D. With decrease in the liquid flow rate for a fixed gas flow rate, the slope of the operating line
decreases, in case of gas absorption process - Pick out the wrong statement?
A. In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated
liquid feed and horizontal feed line represents saturated vapour feed
B. In small columns, local efficiency is larger than Murphree efficiency; in large columns local
efficiency is smaller than Murphree efficiency
C. For Laminar flow over a plate of length L, the local mass transfer co-efficient at a distance L
from the leading edge is 1.5 × 10-2m/s. Then the average mass transfer co-efficient for the
plate is 2 × 10-2m/s
D. The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness,
if Schmidt number is equal to unity - 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 - Pick out the wrong statement ?
A. The mole fraction of solute is directly proportional to the molality of a ‘dilute’ solution
B. For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both
components is nonlinear in the case of steady state unimolal unidirectional diffusion
C. Azeotropes obey Raoult’s law at all temperature
D. The relative volatility of a binary mixture at the Azeotropic composition is 1
