chemical engineering mass transfer MCQs – Page 30

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 Review each marked answer and report any item that may be outdated or unclear.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

581. The-relative volatility for separation of a non-ideal binary mixture by distillation should be ___________________?
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A. 1

B. 0

C. > 1

D. < 1

582. One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoults law is obeyed, then changing the feed composition would effect ?
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A. The product composition as well as the fraction vaporised

B. The fraction vaporised but not the product composition

C. The product composition but not the fraction vaporised

D. Neither the product composition nor the fraction vaporised

583. Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for_________________?
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A. All A., B. and C.

B. Constant relative volatility

C. Constant molal overflow

D. Total reflux

584. Pick out the wrong statement?
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A. orption tower, then the upper end of the operating line touches the equilibrium curve

B. With decrease in the liquid flow rate for a fixed gas flow rate, the slope of the operating line

C. io is also large in case of a counter current gas absorption tower

D. reases, in case of gas absorption process

E. The average distance between the operating line and equilibrium line is large, when the liquidgas

F. When the concentration difference for the mass transfer becomes zero at the bottom of the gas

585. If the amount of the steam used in steam distillation is increased, the temperature of distillation__________________?
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A. Depends on relative volatility

B. Remains unchanged

C. Increases

D. Decreases

586. Which of the following is an undesirable property for an absorbing solvent ?
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A. Low velocity

B. Low vapour pressure

C. Low freezing point

D. None of these

587. Radioactive nuclear waste is treated in____________________?
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A. Pulsed column extractor

B. Bollman extractor

C. Rotating-disc contactor

D. Mixer-settler extractor

588. Only small amount of evaporation of water produces large cooling effects because of its___________________?
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A. Low viscosity

B. Large latent heat

C. None of these

D. Small latent heat

589. Pick out the correct statement ?
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A. Dialysis process is used for the production of fresh water from brine

B. Electrodialysis is used in the manufacture of NaOH

C. Electrodialysis is used for the refining/purification of petrol

D. Both B. and C.

590. In continuous distillation, the internal reflux ratio (Ri) and the external reflux ratio (Re) are related as_____________________?
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A. Ri = Re

B. Ri = Re/(1 + Re)

C. Ri = (1 Re)/Re

D. Ri = Re/(1 Re)

591. For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because__________________?
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A. Solubility of the components of air in water is very small

B. They are always equal under all circumstances

C. Water has a high latent heat of evaporation

D. Lewis number is close to unity

592. Which of the following mixtures does not form an azeotrope at atmospheric pressure ?
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A. Water-alcohol

B. Methyl alcohol-acetone

C. Butyl acetate-water

D. None of these

593. For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of _______________ microns (1 mm = 1000 microns)?
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A. 10-60

B. 5-Jan

C. 200-300

D. > 500

594. Diffusion in concentrated solutions differs from that in dilute solutions, because of the change in the _______________ with the concentration of the solution?
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A. Degree of ideality

B. Viscosity

C. Both A & B

D. Neither A nor B

595. Capacity of a rotary dryer depends on its __________________?
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A. rpm

B. Inclination with ground surface

C. Both A. and B.

D. Neither A. nor B.

596. For contacting a highly soluble gas with a liquid ____________________?
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A. Either A. or B. would suffice

B. Spray the liquid on gas stream

C. None of these

D. Bubble the gas through liquid

597. Which of the following is the most suitable for extraction in a system having very low density difference ?
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A. Mixer-settler extractor

B. Packed extraction tower

C. Centrifugal extractor

D. strong>. Pulsed extractor

598. Absorption with chemical reaction is involved in the removal of__________________?
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A. Tar from coke oven gas in primary gas coolers using chilled water

B. Ammonia from coke oven gas using refrigerated water

C. Carbon dioxide from gaseous stream using alkaline solution

D. Benzol from coke oven gas using solar oil/wash oil

599. With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature) ?
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A. Decreases

B. Remains unchanged

C. Increases

D. Decreases linearly

600. If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively ?
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A. [RD/(RD + 1)], [xD/(xD + 1)]

B. [xD/(RD + 1)], [RD/(RD + 1)]

C. [xD/(RD + 1)], [(RD + 1)/RD]

D. None of these

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