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Question: For water-ethanol system, the minimum reflux ratio
[A].

is computed from the slope of the upper operating line that is tangent to the equilibrium curve.

[B].

is computed from the intercept of the operating line.

[C].

cannot be computed.

[D].

is the optimum reflux ratio.

Answer: Option A

Explanation:

No answer description available for this question.

Question: A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,
[A].

composition of vapors and that of liquid do not vary throughout the column.

[B].

reboiler load and condenser load are minimum.

[C].

the top and bottom compositions are unchanged with and without total reflux.

[D].

the top and bottom compositions correspond to the maximum enrichment available.

Answer: Option D

Explanation:

No answer description available for this question.

Question: In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer.
[A].

The entire amount of C is transferred to solvent B.

[B].

Less than 2 kg but more than 1 kg of C is transferred to solvent B.

[C].

Less than 1 kg of C is transferred to B.

[D].

No amount of C is tranferred to B.

Answer: Option A

Explanation:

No answer description available for this question.

Question: Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are
[A].

1

[B].

8

[C].

9

[D].

10

Answer: Option C

Explanation:

No answer description available for this question.

Question: An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is
[A].

0.048

[B].

0.079

[C].

0.122

[D].

0.152

Answer: Option D

Explanation:

No answer description available for this question.

Question: A distillation column separates 10000 kg/hr of a benzene-toluene mixture as shown in the figure below :In the figure xF, xD and xW represent the weight fraction of benzene in the feed, distillate and residue respectively. The reflux ratio is
[A].

0.5

[B].

0.6

[C].

1.0

[D].

2.0

Answer: Option B

Explanation:

No answer description available for this question.

Question: At minimum reflux ratio for a given separation
[A].

number of plates is zero.

[B].

number of plates is infinity.

[C].

minimum number of the theoretical plates is required.

[D].

separation is most efficient.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Compound A is extracted from a solution of A + B into a pure solvent S. A Co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 moles of B/hr.m2 and the solvent flow, rate is 400 moles of S/m2. hr. The equilibrium data is represented by Y = 3X2 , where Y is in moles of a A/moles of B and X is in moles A/moles of S. The maximum percentage extraction achieved in the unit is
[A].

25%

[B].

50%

[C].

70%

[D].

90%

Answer: Option B

Explanation:

No answer description available for this question.

Question: 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))
[A].

M(Xo – XF)

[B].

M(Xo/XF)

[C].

M ln(Xo/XF)

[D].

MXo ln(Xo/XF)

Answer: Option D

Explanation:

No answer description available for this question.

Question: A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is
[A].

0.54

[B].

1.04

[C].

1.24

[D].

1.94

Answer: Option C

Explanation:

No answer description available for this question.