chemical engineering mass transfer MCQs – Page 24

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 Review each marked answer and report any item that may be outdated or unclear.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

461. In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit) ?
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A. Straight

B. Parallel

C. Both A. & B.

D. Neither A. nor B.

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

B. Vapour pressure of either component

C. Temperature

D. None of these

463. Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the _______________ moisture?
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A. None of these

B. Critical

C. Bound

D. Unbound

464. _______________ column is used in gas absorption process ?
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A. Bubble cap

B. Packed

C. Wetted wall

D. Sieve/perforated tray

465. Extraction of coffee from its seed is done by___________________?
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A. Liquid-liquid extraction

B. Steam distillation

C. Extractive distillation

D. Leaching

466. 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. None of these

B. Increased reflux ratio

C. Greater degree of separation with a fixed number of trays

D. Increased reboiler load

467. In case of absorption, both the operating and equilibrium lines will be straight for______________?
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A. Dilute solutions

B. None of these

C. Isothermal operation

D. Dilute solutions and isothermal operation

468. _________________ is the separation technique used for desalination of sea water ?
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A. Adsorption

B. Reverse osmosis

C. Thermal diffusion

D. Absorption

469. For absorbing a sparingly soluble gas in a liquid ___________________?
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A. Liquid side mass transfer co-efficient should be increased

B. Liquid side mass transfer co-efficient should be decreased

C. Gas side mass transfer co-efficient should be increased

D. Mass transfer co-efficient must be kept constant

470. When the solvent dissolves very little of solute, then__________________________?
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A. Solvent of low freezing point should be used

B. Large quantity of solvent is required to extract the solute

C. Solvent of low latent heat of vaporisation should be used

D. Very small quantity of solvent is required

471. Pick out the system with minimum boiling azeotrope at 1 atm ?
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A. Hydrochloric acid-water

B. Ethyl alcohol-water

C. Benzene-toluene

D. All A., B. and C.

472. The reciprocal of stripping factor is termed as ________________________?
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A. Absorption factor

B. Murphree efficiency

C. Selectivity index

D. Relative volatility

473. Wetted wall tower experiment determines the__________________?
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A. Molal diffusivity

B. None of these

C. Mass transfer co-efficient

D. Volumetric co-efficient

474. During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the _________________ remains constant ?
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A. Wet bulb temperature

B. Relative humidity

C. None of these

D. Partial pressure of water vapor

475. Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the_________________?
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A. Mass transfer co-efficient

B. Volumetric diffusivity

C. Thermal diffusivity

D. Kinematic viscosity

476. _______________ columns are used for liquid dispersion in a continuous gas phase ?
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A. Bubble cap

B. Packed

C. Sieve plate

D. Pulse

477. The McCabe ?L law states that the____________________?
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A. Linear crystal growth rate depends on the crystal size

B. Linear crystal growth rate does not depend on the crystal size

C. Molar heats of vaporisation of components are nearly equal

D. Linear crystal growth rate depends on the degree of super-saturation

478. Which of the following is a suitable absorbent for removal of H2S from natural gas ?
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A. Monoethanolamine (MEA)

B. Dilute

C. Hot water

D. Vetrocoke solution

479. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid _______________ that in dry packed tower ?
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A. Is greater than

B. Cannot be predicted as data are insufficient

C. Is same as

D. Is lower than

480. The rough value of diffusion co-efficient of water vapor into air at 25C may be about ______________ cm2/sec?
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A. 1.25

B. 0.25

C. 2.5

D. 0.0025

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