chemical engineering mass transfer MCQs – Page 21

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 Review each marked answer and report any item that may be outdated or unclear.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
401. The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases A and B is____________?
comments icon0
A. ?

B. 1

C. 2

D. 0.5

402. The relative humidity of air decreases in-spite of an increase in the absolute humidity, when the____________________?
comments icon0

A. Pressure rises

B. Temperature rises

C. Pressure falls

D. Temperature falls

403. According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to_________________?
comments icon0
A. f/2

B. 2f

C. f

D. 1/f

404. Very tall packed towers are divided into series of beds to___________________?
comments icon0

A. Reduce liquid hold-up

B. Reduce the overall pressure drop

C. Avoid channelling

D. Avoid flooding

405. A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture ?
comments icon0

A. The mixture contain optical isomers

B. The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10

C. The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and mxylene

E. The mixture exhibits an azeotrope at 101.3 kPa
406. In stripping section of continuous distillation column, the_______________________?
comments icon0
A. Liquid is enriched with high boiler

B. None of these

C. Vapour is stripped of low boiler

D. Liquid is stripped of high boiler

407. A minimum boiling azeotrope is exemplified by__________________________?
comments icon0

A. Toluene-benzene

B. Water-isobutyl alcohol

C. None of these

D. Acetone-carbon disulphide
408. Binary distillation involves the mass transfer by ______________________ at the gas-liquid interface?
comments icon0

A. Either A. or B.

B. Unidirectional diffusion from gas to liquid phase

C. A counter diffusion at an almost equal molar rate

D. Unidirectional diffusion from liquid to gas phase

409. In McCabe-Thiele method of theoretical plate calculation for a distillation column, the operating lines of stripping and rectifying sections coincide with the diagonal at ________________ reflux ?
comments icon0

A. Maximum permissible

B. Total

C. Operating

D. Minimum

410. As per Gillilands equation, the diffusivity is___________________?
comments icon0

A. Inversely proportional to P

B. Dependent on the molecular volume & molecular weight of components

C. Directly proportional to T1.5

D. All A , B. & C.
411. 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________________?
comments icon0
A. Ideal gases

B. Non-Newtonian liquids

C. Newtonian liquids

D. Real gases

412. A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process ?
comments icon0

A. Humidity of inlet air

B. Temperature of the solid

C. Flow rate of inlet air

D. Relative humidity of outlet air

413. The Schmidt number which is defined as, ?/? D, is the ratio of the_____________________?
comments icon0
A. Momentum diffusivity to the mass diffusivity

B. Momentum diffusivity to the thermal diffusivity

C. Thermal diffusivity to the mass diffusivity

D. None of these

414. Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be_________________?
comments icon0

A. < 1

B. > 1

C. ? 1

D. 1

415. The percentage humidity is less than the relative humidity only at __________________ percent humidity?
comments icon0

A. Zero

B. Hundred

C. Both zero and hundred

D. None of these

416. Below is given an equilibrium moisture curve of a substance. State which regions represent free moisture and unbound moisture respectively ?
comments icon0

A. IV, II

B. II, III

C. II, IV

D. IV, III

417. Detergent solution is dried to a powder in a ________________________?
comments icon0
A. Spray dryer

B. Spouted bed dryer

C. Tunnel dryer

D. Pan open to atmosphere

418. Sand is dried in foundries in a ______________________drier?
comments icon0

A. Spray

B. Fluidised bed

C. Vacuum

D. Rotary

419. Which of the following binary systems is an example of a maximum boiling azeotrope ?
comments icon0
A. Water-hydrochloric acid

B. Water-ethyl alcohol

C. n-heptane-n-octane

D. Acetone-carbon disulphide

420. Smoke is an example of ___________________?
comments icon0

A. Liquid dispersed in gas

B. Solid dispersed in liquid

C. Gas dispersed in liquid

D. Solid dispersed in gas