chemical engineering MCQs – Page 109

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 Review each marked answer and report any item that may be outdated or unclear.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
2161. In the desorption of highly soluble gas from the liquid, the main resistance will be in the ______________ phase?
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A. Gas

B. Liquid

C. Both A. & B.

D. Neither A. nor B.

2162. Mass transfer co-efficient (K) and diffusivity D. are related according to film theory as______________________?
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A. K ? D1.5

B. K ??D

C. K ? D

D. K ? D2

2163. _______________ column is used in gas absorption process ?
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A. Packed

B. Wetted wall

C. Sieve/perforated tray

D. Bubble cap

2164. The amount of steam required per unit quantity of distillate in case of steam distillation will be reduced by __________________?
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A. Raising the temperature

B. Lowering the total pressure

C. Both A. and B.

D. Neither A. nor B.

2165. The diffusivity, DAB (for component A diffusing in B) is equal to the diffusivity DBA (for component B diffusing in A) for a binary mixture of________________?
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A. Real gases

B. Newtonian liquids

C. Non-Newtonian liquids

D. Ideal gases
2166. Batch tray dryers suffers from the disadvantage of______________________?
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A. Non-uniform & low production rate

B. High labour cost & low heat economy

C. High maintenance cost

D. All a, b & c

2167. The expression, ln(F/W) = ?xF xW [dx/y* x)] is_____________________?
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A. Differential distillation equation

B. For NtoG in absorption for dilute mixture

C. Slope of q-line in McCabe-Thiele method

D. For relative volatility

2168. Prandtl number for water at 20C is about ________________?
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A. 7

B. 150

C. 70

D. 0.7

2169. Humid volume, at a given temperature is a/an _______________ function of humidity?
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A. Inverse

B. Exponential

C. Logarithmic

D. Linear
2170. Pick out the wrong statement ?
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A. A horizontal line on the humidity chart indicates the temperature changes at constant molal

B. idity

C. When water is cooled from 80 to 70C by exposure to the air with a wet bulb temperature of

D. C, then both the approach & the range would be 10C

E. For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature

F. p; adiabatic cooling lines are the same

2171. Rate of leaching increases with increasing______________________?
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A. Pressure

B. Size of the solid

C. Temperature

D. Viscosity of solvent

2172. Stefans law describes the mass transfer by________________?
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A. Diffusion

B. Bulk flow

C. Both A. & B.

D. Neither A. nor B.

2173. For the same process conditions, the reflux ratio of an unlagged distillation column___________________?
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A. Decreases in winter

B. Increases in summer

C. None of these

D. Increases in winter
2174. The term cooling range in a cooling tower refers to the difference in the temperature of____________________?
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A. Cold water leaving the tower and the wet bulb temperature of the surrounding air

B. Hot water entering the tower and the cooled water leaving the tower

C. Hot water entering the tower and the wet bulb temperature of the surrounding air

D. None of these

2175. If f = moles of vapour present per mole of feed, then the slope of feed line is (McCabe- Thiele method) ________________________?
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A. -1/f

B. -f/(1 f)

C. (f 1)/f

D. (1 f)/f

2176. When the feed to a distillation column is a saturated liquid, slope of the feed line is_____________________?
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A. None of these

B. Unity

C. Infinity

D. Zero

2177. Which of the following equipments is not used for gas dispersion ?
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A. Bubble cap tray towers

B. Agitated vessels

C. Perforated sieve tray towers

D. Spray towers
2178. When the psychometric ratio is ______________ then the adiabatic saturation temperature and wet bulb temperature becomes equal?
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A. ?

B. 1

C. 1
2179. Small dia distillation column can be a _________________________?
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A. Sieve tray

B. Bubble cap

C. Packed column

D. Any of these

2180. 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, increases surface area

B. Decreases pressure drop, decreases surface area

C. Increases pressure drop, decreases surface area

D. Decreases pressure drop, increases surface area