chemical engineering mass transfer MCQs – Page 11

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 Review each marked answer and report any item that may be outdated or unclear.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
201. Pick out the wrong statement ?
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A. erally

B. The equilibrium moisture content of the solid can be reduced by increasing the absolute

C. idity</strong>

D. Elution means the desorption of the adsorbed solute by a solvent

E. Change in barometric pressure does not affect the relative humidity

F. In case of a packed tower, the operating velocity is about half of the flooding velocity,

202. Which of the following is not fixed by the process requirements, in the design of absorbers ?
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A. Flow rate of the entering gas

B. Composition of the entering liquid

C. Terminal concentrations of gas stream

D. None of these
203. In steam distillation, the _____________________?
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A. Temperature is 100C

B. Temperature is more than 100 C

C. Product must be immiscible with water

D. Temperature is higher than the boiling point of either component

204. Experimental determination of _______________ is done by wetted wall column method?
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A. Mass transfer co-efficient

B. None of these

C. NTU

D. Diffusion co-efficient

205. Danckwerts developed the ____________________ theory?
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A. Surface renewal

B. None of these

C. Penetration

D. Film

206. When an unsaturated air-water mixture is heated at constant pressure, then ____________________ ?
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A. The partial pressure of water vapour increases

B. The relative humidity decreases

C. The specific humidity decreases

D. The relative humidity increases

207. The critical moisture content in case of drying indicates the _______________ rate period?
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A. Beginning of constant

B. None of these

C. Beginning of falling

D. End of falling

208. Which of the following is not a batch drier ?
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A. Agitated pan drier

B. Vacuum shelf drier

C. Fluidised bed drier

D. Truck drier

209. Which of the following is used for the concentration of rubber latex ?
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A. Agitated film evaporator

B. Short tube evaporator

C. Long tube vertical evaporator

D. Calandria

210. With increase in temperature, the mutual solubility of two liquids_________________?
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A. Decreases

B. Increases

C. Decreases exponentially

D. Remains unchanged

211. When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system ?
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A. As the acetone concentration increases, the solubility curves approach each other

B. Both the phases become identical at a particular common point on both the solubility curves

C. led the plait point

D. The distribution curve which is a plot between x (acetone concentration in one phase) and y

E. etone concentration in other phase) is analogous to x-y curve used in distillation and

F. orption terminates on the x = y diagonal at the concentration of the plait point

212. The expression, y(1 x)/x(1 y) is for_____________________?
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A. Relative volatility

B. Murphree efficiency

C. Absorption factor

D. Selectivity

213. The change in enthalpy, when a unit quantity of gas is absorbed by relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists) is termed as the_________________?
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A. Integral heat of adsorption

B. None of these

C. Differential heat of adsorption

D. Heat of wetting

214. All moisture in a non-hygroscopic material is the ________________ moisture?
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A. Unbound

B. Equilibrium

C. Bound

D. Free

215. 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))_____________?
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A. M(Xo/XF)

B. M ln(Xo/XF)

C. M(Xo XF)

D. MXo ln(Xo/XF)
216. Mass transfer co-efficient is directly proportional to DAB according to the __________ theory?
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A. None of these

B. Penetration

C. Surface-renewal

D. Film
217. Sodium bicarbonate is produced during soda ash manufacture using a _______________ tower?
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A. Baffle

B. Packed

C. None of these

D. Plate

218. The dew point of an unsaturated gas-vapor mixture does not depend upon the _________________ of the mixture?
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A. Total pressure

B. All A, B. and C.

C. Composition

D. Temperature
219. Powdery materials can be guarded against caking tendency on storage by_________________?
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A. Providing minimum percentage of voids

B. Providing irregular grain size

C. None of these

D. Having maximum possible points of contact

220. At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is ________________ percent.?
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A. Between 0 and 100

B. 0

C. 50

D. 100