Mass Transfer

Question: In the layout plan for a vacuum distillation unit, operating at 60 mm Hg, supported by a barometric condenser, the appropriate place for the location of vacuum drum for collecting the distillate will be
[A].

at ground level.

[B].

2 metres above the ground.

[C].

5 metres above ground.

[D].

10 metres above ground.

Answer: Option A

Explanation:

No answer description available for this question.

Question: In an operating distillation column, the
[A].

vapors and liquids are at their dew point and bubble point respectively

[B].

driving force for the liquid flow is its specific weight.

[C].

driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column.

[D].

highest temperature is encountered at the top of the column.

Answer: Option C

Explanation:

No answer description available for this question.

Question: At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent.
[A].

100

[B].

0

[C].

50

[D].

between 0 and 100

Answer: Option B

Explanation:

No answer description available for this question.

Question: In most of the vacuum crystalliser, vacuum is generally produced by means of a
[A].

suction pump

[B].

compressed air jet

[C].

steam jet ejector with a barometric condenser

[D].

none of these

Answer: Option C

Explanation:

No answer description available for this question.

Question: If f is defined as above, then which of the following applies to a feed at dew point ?
[A].

f = 1

[B].

f < 1

[C].

f > 1

[D].

0 < f < 1

Answer: Option A

Explanation:

No answer description available for this question.

Question: Flash distillation is suitable for separating the constituents of a binary system, which
[A].

form minimum boiling azeotrope.

[B].

have very wide boiling points.

[C].

have very close boiling points.

[D].

form constant boiling azeotrope.

Answer: Option B

Explanation:

No answer description available for this question.

Question: If f = moles of vapour present per mole of feed, then the slope of feed line is (Mcabe-Thiele method)
[A].

[B].

[C].

[D].

Answer: Option C

Explanation:

No answer description available for this question.

Question: Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the
[A].

mass transfer co-efficient.

[B].

thermal diffusivity.

[C].

kinematic viscosity.

[D].

volumetric diffusivity.

Answer: Option A

Explanation:

No answer description available for this question.

Question: In case of absorption & stripping, the interface of the liquid & gas phases are present in equilibrium, when the diffusional resistance of __________ is zero.
[A].

interface

[B].

gas phase

[C].

liquid phase

[D].

all ‘a’, ‘b’ & ‘c’

Answer: Option A

Explanation:

No answer description available for this question.

Question: Diffusion in concentrated solutins differs from that in dilute solutions, because of the change in the __________ with the concentration of the solution.
[A].

degree of ideality

[B].

viscosity

[C].

both ‘a ‘& ‘b’

[D].

neither ‘a’ nor ‘b’

Answer: Option C

Explanation:

No answer description available for this question.