401. Desirable value of absorption factor in an absorber is
1
< 1
> 1
0.5
✅ The correct answer is option C.
Mass Transfer MCQs
402. H₂S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H₂S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in metres) corresponding to an operating line given by, y = 5x + 0.001 is
2
1.56
1
0.56
✅ The correct answer is option A.
403. Steady state equimolal counter diffusion is encountered in
Separation of a binary mixture by distillation
Absorption of NH₃ from air by water
All liquid-liquid diffusion systems
All of the above
✅ The correct answer is option A.
404. The falling rate period in the drying of a solid is characterised by
Increase in rate of drying
Increasing temperatures both on the surface and within the solid
Decreasing temperatures
None of these
✅ The correct answer is option B.
405. In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in
Reducing the axial mixing
Increasing the rate of extraction
Maintaining the concentration difference between the two phases
All of the above
✅ The correct answer is option D.
406. Adsorption is an unit operation which generally involves __________ systems.
Liquid-solid
Gas-solid
Fluid-solid
Solid-solid
✅ The correct answer is option C.
407. Langmuir equation is associated with
Leaching
Adsorption
Steam distillation
Multicomponent absorption
✅ The correct answer is option B.
408. Equilibrium-moisture curves of different solids
Are different
Are same
Depend on the humidity of the gas
None of these
✅ The correct answer is option A.
409. It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The equilibrium moisture content of the solid is 5%).
15 min
51 min
71 min
94 min
✅ The correct answer is option C.
410. Drying of refractory is normally carried out in a __________ dryer.
Open pan
Tray
Rotary vacuum
Truck/tunnel
✅ The correct answer is option D.