chemical engineering mass transfer MCQs – Page 34

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 Review each marked answer and report any item that may be outdated or unclear.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

661. Weight of 1 m3 of humid air as compared to 1 m3 of dry air, under the same conditions, is_________________?
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A. More

B. Same

C. Unpredictable

D. Less

662. Percentage saturation is _______________ the relative saturation?
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A. Always smaller than

B. Not related to

C. Always greater than

D. None of these

663. In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapour, because_______________?
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A. dition</strong>

B. Total pressure is less

C. Temperature is less

D. Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium

E. Saturated steam is used for steam distillation

664. Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when____________________?
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A. One of the liquid components is heat sensitive

B. Extracting solvent is cheaply & abundantly available

C. Viscosity of liquid components is very high

D. One of the liquid components has very high affinity towards the solvent

665. In an absorber, HETP does not vary with the____________________?
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A. None of these

B. Flow rate of gas

C. Flow rate of liquid

D. Type and size of packing

666. Pick out the wrong statement?
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A. oding is generally encountered in packed towers

B. Packed towers are preferred over plate towers for handling corrosive and foamy liquids

C. Due to uneven supply and improper distribution of liquid, problem of channelling, loading &

D. Packed towers are preferred for vacuum operation, because the pressure drop through the

E. Diameter of randomly packed tower is normally more than 1.2 metres

F. king is less and they (packings) also lessen the possibility of tower wall collapse

667. Pick out the wrong statement?
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A. Molecular diffusion in solid is much faster than that in liquids

B. Particles movement from higher concentration to lower concentration takes place in diffusion

C. w of a gas through a given capillary

D. According to Poiseuilles law, the permeability decreases with increase in temperature for

E. The binary diffusivity in liquids is of the order of 10-5 cm2/sec

F. cess

668. The term cooling range in a cooling tower refers to the difference in the temperature of____________________?
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A. Hot water entering the tower and the wet bulb temperature of the surrounding air

B. Cold water leaving the tower and the wet bulb temperature of the surrounding air

C. None of these

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

669. Drying operation under vacuum is carried out to __________________?
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A. Dry materials having high bound moisture content

B. Increase drying temperature

C. Dry those materials which have very high unbound moisture content

D. Reduce drying temperature

670. Pick out the correct statement ?
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A. All A., B. and C.

B. reases

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

D. d is unity

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

F. In case of liquid-liquid extraction, no separation is possible, if the selectivity of the solvent

671. The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are __________________?
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A. Parallel

B. Straight

C. Both parallel and straight

D. Neither parallel nor straight

672. Hydrogenation of oil is carried out in a/an _______________ in Vanaspati manufacturing plant?
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A. Sieve tray column

B. Packed tower

C. Bubble cap column

D. Agitated vessel

673. Boiling point diagram is not affected by the ambient______________________?
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A. Pressure

B. Humidity

C. Temperature

D. Both B. and C.

674. On addition of solute in the solvent, the ______________ of the solution decreases ?
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A. Boiling point

B. Freezing point

C. Vapour pressure

D. Both B. and C.

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

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

D. Incurs smaller pressure drop

676. For continuous drying of granular or crystalline material, the dryer used is the _______________ dryer?
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A. Rotary

B. Tunnel

C. None of these

D. Tray

677. At a fixed total pressure, humidity depends only on the _______________________?
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A. None of these

B. Density of the vapour

C. Partial pressure of vapour in the mixture

D. Heat capacity of the vapour

678. Rate of leaching increases with increasing______________________?
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A. Size of the solid

B. Pressure

C. Viscosity of solvent

D. Temperature

679. The rate of solid-liquid extraction is limited by the_________________?
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A. Phase change of the solute as it dissolves in the solvent

B. Diffusion of the solute from the solution in contact with the particle to the main bulk of the

C. ution

D. Diffusion of the solute through the solvent in the pores to the outside of the particle

E. All A , B. & C.

680. Extraction of penicillin employs a ________________ extraction column?
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A. Plate

B. Centrifugal

C. Packed

D. None of these

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