101. The Knudsen diffusivity is dependent on the
Molecular velocity only
Pore radius of the catalyst only
Molecular mean free path only
Molecular velocity and por radius of the catalyst
✅ The correct answer is option D.
Mass Transfer MCQs
102. In case of constant underflow extraction operation, the __________ at all solute concentration.
Solids are drained to the same extent
Ratio of the insoluble to solution is constant
Both A & B
Neither A nor B
✅ The correct answer is option C.
103. The cooling effect in a cooling tower can not be increased by
Increasing the air velocity over the wet surfaces
Reducing the humidity of entering air
Lowering the barometric pressure
None of these
✅ The correct answer is option D.
104. Penetration model (theory) for mass transfer was enunciated by
Danckwerts
Toor and Marchello
Higbie
Kissinevskii
✅ The correct answer is option C.
106. When a multistage tray tower uses a minimum reflux ratio, it implies
Infinite trays and maximum reboiler heat load
Infinite trays and minimum reboiler heat load
Minimum trays and minimum reboiler heat load
Minimum trays and maximum reboiler heat load
✅ The correct answer is option A.
107. Entrainer used in azeotropic distillation should
Form a low boiling azeotrope with one of the constituents of the mixture
Form a new azeotrope of low relative volatility with one of the constituents of the mixture
Have high latent heat of vaporisation
Have high viscosity to provide high tray efficiency
✅ The correct answer is option A.
108. Flooding results in
High tray efficiency
Low tray efficiency
High gas velocity
Good contact between the fluids
✅ The correct answer is option B.
109. Large scale drying of sugar is done in a __________ dryer.
Spouted bed
Tray
Rotary
Truck
✅ The correct answer is option C.
110. Very tall packed towers are divided into series of beds to
Reduce the overall pressure drop
Avoid channelling
Reduce liquid hold-up
Avoid flooding
✅ The correct answer is option B.