321. Decoction refers to the use of solvent
At ambient temperature
At its boiling point
In its vapor form
None of these
✅ The correct answer is option B.
Mass Transfer MCQs
322. Which of the following same diameter columns gives lowest pressure drop per unit height?
Bubble-cap column
Sieve-plate column
Packed column (stacked)
Randomly packed column
✅ The correct answer is option C.
323. The mass transfer co-efficient for a solid sphere of radius ‘a’ dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is
D/a
D/2a
Proportional to √D
Dependent on the Reynolds number
✅ The correct answer is option D.
324. The most efficient cooling tower out of the following is
Induced draft
Forced draft
Natural draft
Atmospheric
✅ The correct answer is option A.
325. In the desorption of highly soluble gas from the liquid, the main resistance will be in the __________ phase.
Gas
Liquid
Both A & B
Neither A nor B
✅ The correct answer is option B.
326. A slurry is to be dried to produce flaky solid. Which dryer would you recommend?
Spray dryer
Drum dryer
Rotary dryer
Dielectric dryer
✅ The correct answer is option A.
327. Mass transfer co-efficient (K) and diffusivity (D) are related according to film theory as
K ∝ D
K ∝ √D
K ∝ D1.5
K ∝ D2
✅ The correct answer is option A.
328. The velocity, concentration and temperature boundary, for the boundary layer development on a flat plate during connective mass transfer will be same, if
NSc = 1
NSc = NPr = NLe
NPr = NLe
NSc = NLe
✅ The correct answer is option B.
329. As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches
That of normal condensation
Integral heat of adsorption
Zero
None of these
✅ The correct answer is option A.
330. The Kundsen diffusivity is proportional to (where, T = absolute temperature)
√T
T²
T
T⁴
✅ The correct answer is option A.