CHEMICAL ENGINEERING

Question: According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the coloumn.
[A].

5

[B].

9

[C].

12

[D].

28

Answer: Option C

Explanation:

No answer description available for this question.

Question: In a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raf-finate phase R containing A at xB = 0.5 and xR = 0.05 respectively. The total mass of the extract phase is (in Kg)
[A].

6.89

[B].

8.89

[C].

10

[D].

8.25

Answer: Option B

Explanation:

No answer description available for this question.

Question: In Mcabe-Thiele method, at infinite reflux ratio
[A].

number of plates is maximum.

[B].

overhead product is maximum.

[C].

both the operating lines coincide with the diagram.

[D].

none of these.

Answer: Option C

Explanation:

No answer description available for this question.

Question: An alkaline solution is used to reduce the concentration of carbon dioxide in a stream from 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is
[A].

9.21

[B].

4.605

[C].

100

[D].

0.001

Answer: Option B

Explanation:

No answer description available for this question.

Question: A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?
[A].

The mixture exhibits an azeotrope at 101.3 kPa.

[B].

The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10.

[C].

The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10.

[D].

The mixture contain optical isomers.

Answer: Option A

Explanation:

No answer description available for this question.

Question: One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect
[A].

the product composition but not the fraction vaporised.

[B].

the product composition as well as the fraction vaporised.

[C].

the fraction vaporised but not the product composition.

[D].

neither the product composition nor the fraction vaporised.

Answer: Option C

Explanation:

No answer description available for this question.

Question: As the reflux ratio increases, the slope of the operating line for rectifying section
[A].

increases

[B].

decreases

[C].

remains constant

[D].

data insufficient, cannot be predicted

Answer: Option A

Explanation:

No answer description available for this question.

Question: According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity)
[A].

D

[B].

D2

[C].

D0.5

[D].

1/D

Answer: Option A

Explanation:

No answer description available for this question.

Question: In distillation columns, the number of bubble caps per tray primarily depends upon the
[A].

allowable liquid velocity.

[B].

allowable gas velocity.

[C].

allowable gas and liquid velocities.

[D].

feed composition.

Answer: Option C

Explanation:

No answer description available for this question.

Question: For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as
[A].

Re0.33

[B].

Re0.53

[C].

Re0.83

[D].

Re

Answer: Option C

Explanation:

No answer description available for this question.