chemical engineering mass transfer MCQs – Page 15

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 Review each marked answer and report any item that may be outdated or unclear.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
281. Desirable value of absorption factor in an absorber is___________________?
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A. > 1

B. < 1

C. 1

D. 0.5

282. Components, having widely different boiling point in a binary mixture, can be separated using ________________ distillation?
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A. Steam

B. Extractive

C. Molecular

D. Simple
283. The falling rate period in the drying of a solid is characterised by__________________?
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A. Increase in rate of drying

B. Increasing temperatures both on the surface and within the solid

C. Decreasing temperatures

D. None of these

284. According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity) ?
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A. D2

B. D

C. D0.5

D. 1/D

285. The dew point of a saturated gas phase equals the ________________ temperature?
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A. Room

B. None of these

C. Wet bulb

D. Gas
286. For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as___________________?
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A. Re0.53

B. Re0.83

C. Re

D. Re0.33

287. Advantage of continuous drying over batch drying is that the_____________________?
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A. Equipment size required is smaller

B. Drying cost per unit weight of dried product is less

C. All A , B. & C.

D. Product with more uniform moisture content is produced

288. Surface renewal model of mass transfer was enunciated by___________________?
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A. Danckwerts

B. Fick

C. Toor and Marcello

D. Stefan

289. For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams__________________?
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A. Increases

B. Decreases

C. Remain unaffected

D. Passes through a maximum

290. ADDUCTS and CLATHRATES are used in case of_____________________?
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A. Absorption

B. Extractive distillation

C. Crystallisation

D. None of these

291. Separation of the isotopes of helium for scientific investigations is done by_____________________?
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A. Thermal diffusion

B. Solvent extraction

C. Reverse osmosis

D. Leaching

292. The wetted wall tower is used to determine_________________________?
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A. The overall M.T.C. of the system

B. M.T.C. of individual components in a liquid-liquid system

C. Individual mass transfer co-efficient (M.T.C.) in gaseous system

D. M.T.C. of liquid in liquid-gas system

293. Dry bulb temperature of the gas is _____________ the wet bulb temperature?
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A. Less than

B. Equal to

C. More than

D. None of these

294. Degree of freedom for leaching and solvent extraction process is_____________________?
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A. 1

B. 3

C. 0

D. 2

295. Flooding in a distillation column is detected by a sharp ___________________?
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A. Increase in pressure drop

B. Increase in Murphree plate efficiency

C. Decrease in liquid hold up in the column

D. Decrease in pressure drop

296. Drift in a cooling tower is ___________________?
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A. The water entrained by the circulating air

B. Dependent on the water lost by evaporation

C. Desirable

D. All A., B. & C.

297. Adsorption is a unit operation which generally involves _______________ systems?
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A. Fluid-solid

B. Gas-solid

C. Solid-solid

D. Liquid-solid

298. Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) ?
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A. Increases pressure drop, decreases surface area

B. Decreases pressure drop, decreases surface area

C. Decreases pressure drop, increases surface area

D. Increases pressure drop, increases surface area

299. Make up water is required in a cooling tower to replace the water lost by___________________?
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A. Drift

B. Evaporation

C. Blowdown and leakage

D. All A., B. and C.
300. Nitrobenzene (boiling point = 210.6C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off _______________ C?
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A. At < 100

B. Between 100 and 210

C. None of these

D. At > 210.6