chemical engineering mass transfer Mcqs
303. Out of two equilibrium curves, first one lies above the diagonal and the second lies below the diagonal in the x-y plot. It means that separation by distillation is_________________?
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A. None of these

B. Not possible in the second case unless vacuum is applied

C. Not possible in the second case unless high pressure is applied

D. More readily done in the second case compared to first one
304. Raoults law is applicable to the_____________________?
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A. Non-ideal gases

B. Ideal solutions

C. Real solutions

D. Mixture of water and alcohol

305. Pick out the wrong statement ?
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A. tillation column at normal operating reflux condition</strong>

B. brane is called dialysis

C. Freeze drying is used for the drying of fish

D. Fenske-Underwood equation is used for calculating theoretical number of plates in a

E. Reboiler is not used in open steam distillation

F. The separation of solutes of different molecular sizes in a liquid solution by use of a suitable

306. When the liquid phase and vapour phase of a binary system obeys Raoults and Daltons law respectively, the relative volatility is the ratio of________________________?
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A. Vapour pressure of component A to the total pressure

B. Vapour pressure of component A to the partial pressure of A

C. Partial pressure of component A to the total pressure

D. Vapour pressure of component A to that of component B
307. Flash distillation is suitable for the separation of components_________________?
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A. Having very close boiling points

B. Having very wide boiling points

C. Which form minimum boiling azeotrope

D. Which form maximum boiling azeotrope

309. McCabe-Thiele method________________?
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A. Can use any type of units

B. Is more accurate than Ponchon-Savarit method

C. Uses weight fractions to express liquid and vapour composition

D. Uses molal units for material and energy balance
310. Agitator is provided in a crystalliser for____________________?
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A. All A., B. and C.

B. Crystal growth

C. Formation of nuclei

D. Avoiding deposition on cooler surfaces

312. Which of the following assumes constant molal vaporisation and overflow ?
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A. Ponchan-Savarit method

B. Plate absorption column

C. McCabe-Thiele method

D. Enthalpy concentration method

313. Equilibrium-moisture curves of different solids ____________________ ?
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A. Are different

B. None of these

C. Depend on the humidity of the gas

D. Are same

314. For an absorber, both equilibrium and operating line will be straight for _______________________?
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A. Dilute solution and non-isothermal operation

B. Dilute solution and isothermal operation

C. Concentrated solution and isothermal operation

D. Concentrated solution and non-isothermal operation

315. In a packed bed absorption column, the channelling will be noted by the ____________________?
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A. None of these

B. Increase in flow rate

C. Sharp drop in pressure drop

D. Sharp rise in pressure drop

317. Channelling is most severe_____________________?
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A. At very high liquid flow rate

B. In towers packed with stacked packing

C. In dumped packing of regular units

D. In towers packed randomly with crushed solids

319. The expression, ln(F/W) = ?xF xW [dx/y* x)] is_____________________?
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A. Differential distillation equation

B. For NtoG in absorption for dilute mixture

C. Slope of q-line in McCabe-Thiele method

D. For relative volatility

321. Which is the controlling factor for a drum drier ?
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A. Diffusion

B. Heat transfer

C. Both A. and B.

D. Neither A. nor B.

322. Relative humidity is the ratio of the______________________?
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A. Partial pressure of the vapour to the vapour pressure of the liquid at room temperature

B. Partial pressure of the vapour to the vapour pressure of the liquid at gas temperature

C. Actual humidity to saturation humidity

D. None of these

329. Can a cooling tower cool water below the wet bulb temperature of inlet air ?
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A. Yes; but height of cooling tower will be prohibitively high

B. Yes

C. Yes; but the air flow rate should be excessively high

D. No
330. The shanks system of leaching (i.e., counter-current multiple contact leaching) is used for____________________?
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A. Recovery of tannis from the tree barks and woods

B. Leaching sodium nitrate from Chilean nitrate bearing rock

C. Both A. and B.

D. Neither A. nor B.

331. Fenske equation for determining the minimum number of theoretical stages in distillation column holds good, when the_________________?
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A. Mixture (to be separated) shows positive deviation from ideality

B. Mixture (to be separated) shows negative deviation from ideality

C. Relative volatility is reasonably constant

D. Multi-component distillation is involved

332. Unit of molal diffusivity is____________________?
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A. cm2/sec gm . mole

B. gm moles/cm. sec

C. gm moles/cm2. sec

D. gm moles/cm2 . sec

335. Under conditions of flooding in packed tower, the gas pressure drop___________________?
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A. Decreases rapidly

B. Is maximum

C. Remain constant

D. Increases rapidly

336. For a distillation column operating at minimum reflux, the_______________________?
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A. Reflux ratio will be maximum

B. None of these

C. Number of plates required will be maximum

D. Concentration of liquid and vapour leaving a plate will be same

339. Priming in a distillation column_________________?
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A. Is desirable from point efficiency consideration

B. Results from very low gas velocity

C. Is characterised by the presence of foam throughout the space between trays

D. Reduces the overall pressure drop

343. Absorption accompanied by heat evolution results in____________________?
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A. Decrease in equilibrium solubility

B. None of these

C. Increased capacity of the absorber

D. Increase in equilibrium solubility

348. In distillation columns, the number of bubble caps per tray primarily depends upon the_______________________?
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A. Allowable gas velocity

B. Allowable gas and liquid velocities

C. Feed composition

D. Allowable liquid velocity

349. __________________ is concerned with the adsorption equilibria?
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A. Gibbs equation

B. Freundlich equation

C. None of these

D. Ficks law