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
Related Mcqs:
- 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?
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 - Pick out the wrong statement?
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 - Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________?
transfer operations.
A. Sherwood number in mass transfer is analogous to Nusselt number in heat transfer
B. Prandtl number in heat transfer is analogous to Schmidt number in mass transfer
C. Reynolds number in mass transfer is analogous to Grashoff number in heat transfer
D. Reynolds number remains the same in both heat and mass transfer - Pick out the wrong statement. Raoult’s law does not apply, when the______________________?
A. Size of component molecules are not equal
B. Attractive forces between like and unlike molecules in the solution are approximately equal
C. Component molecules are non-polar
D. Chemical combination or molecular association between unlike molecules takes place in the
formation of solution - 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. 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. Cellulose acetate membranes are used in dialysis process
B. Elutriation process refers to when the soluble material is largely concentrated on the surface of
an insoluble solid and is simply washed off by the solvent
C. ‘Cascade’ means a group of stages interconnected so that various streams flow from one to
another
D. Zirconia probe is used for the humidity measurement - 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
