The Lewis number is the ratio of
A.thermal diffusivity to mass diffusivity
B.mass diffusivity to thermal diffusivity
C.mass diffusivity to momentum diffusivity
D.momentum diffusivity to thermal diffusivity
Category: Mass Transfer Mcqs
The diffusivity of a constituent A in solution B has the units.
A.m/s
B.m2/s
C.m3/s
D.kmol/(m2-s)
At the boiling point of the liquid at the prevailing pressure the saturated absolute humidity becomes
A.one
B.zero
C.infinity
D.none of the above
At total reflux the capacity of a distillation colum is
A.zero and one
B.maximum
C.minimum
D.optimum
If q is interpreted to be the fraction of the feed that is liquid then the slope of the feed line in distillation operation is
A.?(1-q)/q
B.?q/(1-q)
C.?q
D.?q/(q-1)
The steady-state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is called
A.dry-bulb temperature
B.dew point
C.wet-bulb temperature
D.bubble point
Which of the following systems is an example of minimum boiling azeotrope at 1 atm?
A.Carbon disulphide-acetone
B.Ethanol-water
C.Benzene-ethanol
D.Acetone-chloroform
The Schmidt number (NSc) is the ratio of
A.the momentum diffusivity to the mass diffusivity
B.the mass diffusivity to the momentum diffusivity
C.the thermal diffusivity to the mass diffusivity
D.the momentum diffusivity to the thermal diffusivity
Relative volatility ? for a binary system
A.decreases with increase in pressure
B.increases with increase in pressure
C.increases with increase in temperature at constant pressure
D.has no significance in distillation operation
