chemical engineering mass transfer MCQs – Page 6

Practise multiple-choice questions from chemical engineering mass transfer for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering mass transfer Mcqs
101. Minimum reflux ratio in a distillation column results in__________________?
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A. Maximum condenser size

B. Minimum number of trays

C. Minimum reboiler size

D. Optimum number of trays

102. The diffusivity D. in a binary gas mixture is related to the pressure (P) as___________________?
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A. D ? 1/P

B. D ? 1/P1.5

C. D ? 1/P0.5

D. D ? P0.5

103. Which of the following is directly concerned with Psychrometry ?
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A. Lewis relationship

B. Dean number

C. Galileo number

D. Weber number

104. Bound moisture is that liquid which exerts an equilibrium vapor pressure ________________ that of the pure liquid at the given temperature ?
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A. Either A. or B.; depends on the solid

B. Equal to

C. More than

D. Less than
105. A binary mixture of benzene and cyclohexane is separated by___________________?
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A. Solvent extraction

B. Ordinary distillation

C. Extractive distillation

D. Flash vaporisation

106. Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.) ?
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A. (1 + Ri) = Ro/Ri

B. (1 + Ro) = Ro/Ri

C. (1 Ri) = Ro/Ri

D. (1 Ro) = Ro/Ri

107. Dimension of mass diffusivity is the same as that of_____________________?
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A. Kinematic viscosity

B. Pressure

C. Dynamic viscosity

D. Surface tension

108. Laboratory determination of the diffusivity of vapor is done by __________________ method?
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A. Wetted wall column

B. Winkelmanns

C. Wikes

D. Gillilands

109. For absorbing a sparingly soluble gas in a liquid, the_____________________?
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A. Liquid side coefficient should be increased

B. Liquid side co-efficient should be decreased

C. Gas side co-efficient should be decreased

D. Gas side co-efficient should be increased

110. Leaching of uranium ore and gold ore is done in_____________________?
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A. Pachuca tanks

B. Centrifugal extractor

C. Bollman extractor

D. None of these

111. The apex of an equilateral-triangular coordinate (in ternary liquid system) represents a/an ___________________?
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A. Binary mixture

B. Ternary mixture

C. Insoluble binary system

D. Pure component
112. In case of constant underflow extraction operation, the _______________________ at all solute concentration?
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A. Solids are drained to the same extent

B. Ratio of the insoluble to solution is constant

C. Both A. & B.

D. Neither A. nor B.

113. Which of the following is an undesirable property in a tower packing ?
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A. Large weight of liquid retained

B. Large free cross-section

C. Large surface per unit volume

D. Low weight per unit volume

114. 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_____________________?
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A. 2 metres above the ground

B. At ground level

C. 10 metres above ground

D. 5 metres above ground

115. In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in_________________?
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A. Maintaining the concentration difference between the two phases

B. All A , B & C.

C. Reducing the axial mixing

D. Increasing the rate of extraction

116. The drying time between fixed moisture content within diffusion controlled falling rate period is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid) ?
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A. T2

B. ?T

C. T3

D. T

117. Mass transfer co-efficient K according to penetration theory varies with mass diffusivity as____________________?
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A. 1/D

B. D1.5

C. D0.5

D. D

118. For a ternary mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a _______________ of the equilateral triangular co-ordinates?
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A. Binary mixture is represented by any point inside

B. Ternary mixture is represented by the sides

C. Binary mixture is represented by the apex

D. Pure component is represented by the apex
119. Raoults law does not apply, when the___________________?
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A. Component molecules are non-polar

B. Size of component molecules are not equal

C. Chemical combination or molecular association between unlike molecules takes place in the

D. Attractive forces between like and unlike molecules in the solution are approximately equal

E. mation of solution

120. The ratio of Murphree plate efficiency to point efficiency is 1 in a ______________________ flow model?
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A. Plug

B. Perfectly mixed

C. Both A. & B.

D. Neither A. nor B.