611. The ratio of Murphree plate efficiency to point efficiency is always > 1 in a __________ flow model.
Plug
Perfectly mixed
Both A & B
Neither A nor B
✅ The correct answer is option A.
Mass Transfer MCQs
612. The diffusion co-efficient in m² /s. of acetic acid in benzene (liquid in liquid) is
2.09 x 10-4
2.09 x 10-5
2.09 x 10-9
2.09 x 10-12
✅ The correct answer is option A.
613. For absorbers, high pressure drop results in
Increased efficiency
Decreased efficiency
High operating cost
Better gas liquid contact
✅ The correct answer is option C.
614. In case of a desorber (stripper), the
Operating line always lies above the equilibrium curve
Operating line always lies below the equilibrium curve
Temperature remains unaffected
Temperature always increases
✅ The correct answer is option B.
615. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids)
M(Xo – XF)
M(Xo/XF)
M ln(Xo/XF)
MXo ln(Xo/XF)
✅ The correct answer is option D.
616. The ‘shanks system’ of leaching (i.e., counter-current multiple contact leaching) is used for
Recovery of tannis from the tree barks and woods
Leaching sodium nitrate from Chilean nitrate bearing rock
Both A & B
Neither A nor B
✅ The correct answer is option C.
617. The diffusivity, DAB (for component A diffusing in B) is equal to the diffusivity Dsub>BA (for component B diffusing in A) for a binary mixture of
Newtonion liquids
Non-Newtonion liquids
Ideal gases
Real gases
✅ The correct answer is option C.
618. Dew point of an air-water vapor mixture
Decreases with decrease in pressure
At constant humidity & total pressure is fixed
Corresponding to any point on the humidity chart is obtained by projecting a line through this point parallel to the temperature axis and to the saturation curve
All of the above
✅ The correct answer is option D.
619. With increase in temperature, the leaching rate increases because of the
Increased diffusivity
Decreased viscosity of liquid
Both A and B
Neither A nor B
✅ The correct answer is option C.
620. Which of the following is an undesirable property in a tower packing?
Large surface per unit volume
Large free cross-section
Low weight per unit volume
Large weight of liquid retained
✅ The correct answer is option D.