chemical engineering MCQs – Page 111

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
2201. The film penetration model of mass transfer was enunciated by______________________?
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A. Gilliland

B. Fick

C. Toor and Marcello

D. Stefan

2202. Pick out the correct statement ?
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A. In case of liquid-liquid extraction, no separation is possible, if the selectivity of the solvent

B. All A., B. and C.

C. d is unity

D. With increase in temperature, the selectivity of the solvent used in solvent extraction

E. reases

F. The selectivity of solvent used in solvent extraction is unity at the plait point

2203. Absorption factor is defined as (where, S1 = slope of the operating line S2 = slope of the equilibrium curve) ____________________?
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A. S1 S2

B. S2/S1

C. S1 S2

D. S1/S2
2204. In distillation, overhead product contains ______________________?
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A. Only saturated liquid

B. Only one component

C. Any number of components

D. Two components

2205. Pick out the system with minimum boiling azeotrope at 1 atm ?
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A. Benzene-toluene

B. Ethyl alcohol-water

C. Hydrochloric acid-water

D. All A., B. and C.

2206. Minimum possible diameter of a packed column is decided mainly by the________________________?
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A. Liquid hold up

B. Liquid density

C. Gas viscosity

D. Flooding
2207. Channelling is most severe_____________________?
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A. In dumped packing of regular units

B. In towers packed with stacked packing

C. At very high liquid flow rate

D. In towers packed randomly with crushed solids

2208. Molarity is defined as the number of gm moles of solute per ________________ of solvent?
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A. kg

B. c.c

C. gm

D. Litre
2209. A mixture of 10% C6H6 vapour in air at 25C and 750 mm Hg has a dew point of 20C. Its dew point at 30C and 700 mm Hg will be around _______________ C?
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A. 27.3

B. 21.7

C. 20

D. 18.7
2210. If the amount of the steam used in steam distillation is increased, the temperature of distillation__________________?
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A. Decreases

B. Depends on relative volatility

C. Increases

D. Remains unchanged

2211. (NRe . NSc) is termed in mass transfer operation as the ______________ number?
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A. Peclet

B. Stanton

C. Sherwood

D. None of these

2212. On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in______________________?
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A. Greater degree of separation with a fixed number of trays

B. None of these

C. Increased reflux ratio

D. Increased reboiler load

2213. 1 kg of a saturated aqueous solution of a highly soluble component A at 60C is cooled to 25C. The solubility limits of A are (0.6 kgA/kg water) at 60C and (0.2 kgA/kg water) at 25C. The amount in kg of the crystals formed is________________________?
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A. 0.25

B. 0.175

C. 0.4

D. 0.2
2214. Which of the following is an undesirable characteristic for the solvent used in gas absorption ?
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A. Low viscosity

B. High gas solubility

C. None of these

D. Low vapor pressure

2215. At what value of reflux ratio, number of theoretical plates in a distillation column is minimum ?
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A. < 1

B. ?

C. 0

D. 1

2216. A packed tower compared to a plate tower for a particular mass transfer operation__________________?
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A. Allows installation of cooling coils

B. Incurs smaller pressure drop

C. Is less costly when built in large sizes/diameters

D. Is more suitable, if suspended solids are present in fluid streams

2217. Which of the following unit operations makes use of Thiele-Geddes equation ?
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A. Multi-component distillation

B. Multi-component absorption with chemical reaction

C. Liquid-liquid extraction

D. Solid-liquid extraction

2218. Relative volatility does not change appreciably with the change in_____________________?
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A. Total pressure

B. Vapour pressure of either component

C. None of these

D. Temperature
2219. In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter ?
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A. > 8:1

B. < 6:1

C. < 8 : 1

D. > 4 :1

2220. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = _________________?
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A. 1

B. 0.5

C. 0

D. 10