Q.1
The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around
Q.2
Molality is defined as the number of gm moles of solute per __________ of solvent.
Q.3
Deairation (removal of O₂) of water is done by
Q.4
Radioactive nuclear waste is treated in
Q.5
Unit operation involved in the prilling of urea is
Q.6
Danckwerts developed the __________ theory.
Q.7

Which of the following is a suitable absorbent for removal of H2S from natural gas ?

  • Vetrocoke solution
  • Monoethanol amine (MEA)
  • Dilute
  • Hot water
Q.8

In a gas-liquid absorption coloumn, for obtaining the maximum absorption efficiency

  • liquid stream should be distributed uniformly.
  • gas stream should be distributed uniformly.
  • both gas as well as liquid streams should be distributed uniformly.
  • by passing should be completely avoided.
Q.9

Unsaturated air (with dry and wet bulb temperatures beingand 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be

  • cooled
  • humidified
  • both (a) & (b)
  • dehumidified
Q.10

Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).Forrecovery of acetone, the number of trays required is/are

  • 1
  • 8
  • 9
  • 10
Q.11

Reverse osmosis is also called

  • dialysis
  • electrodilysis
  • diffusion
  • ultrafiltration.
Q.12

Which of the following is not a batch drier?

  • Truck drier
  • Agitated pan drier
  • Fluidised bed drier
  • Vacuum shelf drier
Q.13

For absorbing a sparingly soluble gas in a liquid, the

  • gas side co-efficient should be increased.
  • liquid side coefficient should be increased.
  • gas side co-efficient should be decreased.
  • liquid side co-efficient should be decreased.
Q.14

A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height.

  • 10-15
  • 30-40
  • 70-80
  • 90-100
Q.15

Schimdt number and Lewis number for pure air at atmospheric conditions are respectively

  • < 1 and ≈ 1
  • 1 and 0
  • >1 and ≈ 1
  • 0 and ≈ 1
Q.16

Extraction of coffee from its seed is done by

  • liquid-liquid extraction.
  • leaching.
  • extractive distillation.
  • steam distillation.
Q.17

If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are

  • straight
  • parallel
  • both (a) & (b)
  • neither (a) nor (b)
Q.18

Which of the following assumes constant molal vaporisation and overflow ?

  • McCabe-Thiele method
  • Ponchan-Savarit method
  • Enthalpy concentration method
  • Plate absorption column
Q.19

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

  • not possible in the second case unless vacuum is applied.
  • not possible in the second case unless high pressure is applied.
  • more readily done in the second case compared to first one.
  • none of these
Q.20

Steam distillation is not recommended to be used, if the

  • azeotropic mixture is to be separated and the final product is miscible with water.
  • liquids decompose, if distilled directly at atmospheric pressure.
  • material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature.
  • material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature.
Q.21

The boiling points of pure components of a binary system __________ with increase in total pressure of the system.

  • decreases
  • increases
  • remains unchanged
  • may increase or decrease, depends on the system.
Q.22

Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve.

  • 100
  • 50
  • 78
  • none of these
Q.23

In azeotropic mixture, the equilibrium vapour composition is

  • more than liquid composition.
  • less than liquid composition.
  • same as liquid composition.
  • independent of pressure.
Q.24

Which of the following operations does not involve leaching ?

  • Dissolving gold from ores.
  • Dissolving pharmaceutical products from bark or roots.
  • Dissolving sugar from the cells of the beet.
  • Removing nicotine from its water solution by kerosene.
Q.25

Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be

  • 1
  • > 1
  • < 1
  • ≤ 1
Q.26

Selectivity of the solvent used in solvent extraction should be

  • 1
  • > 1
  • < 1
  • 0
Q.27

'ADDUCTS' and 'CLATHRATES' are used in case of

  • extractive distillation.
  • crystallisation.
  • absorption.
  • none of these.
Q.28

Adsorption is an unit operation which generally involves __________ systems.

  • liquid-solid
  • gas-solid
  • fluid-solid
  • solid-solid
Q.29

Pick out the wrong statement. Raoult's law does not apply, when the

  • size of component molecules are not equal.
  • attractive forces between like and unlike molecules in the solution are approximately equal.
  • component molecules are nonpolar.
  • chemical combination or molecular association between unlike molecules takes place in the formation of solution.
Q.30

Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.

  • rotary
  • vacuum
  • tunnel
  • tray
Q.31

Can a cooling tower cool water below the wet bulb temperature of inlet air ?

  • yes
  • no
  • yes ; but height of cooling tower will be prohibitively high.
  • yes ; but the air flow rate should be excessively high.
Q.32

Dry bulb temperature of the gas is __________ the wet bulb temperature.

  • less than
  • more than
  • equal to
  • none of these
Q.33

Rayleigh equation applies to __________ distillation.

  • differential
  • flash
  • equilibrium
  • molecular
Q.34

The change in enthalpy, when a unit quantity of gas is absorbed by relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists) is termed as the

  • differential heat of adsorption.
  • heat of wetting.
  • integral heat of adsorption.
  • none of these.
Q.35

Flooding in a column results due to

  • high pressure drop
  • low pressure drop
  • low velocity of the liquid
  • high temperature
Q.36

Molecular diffusion is caused by the

  • transfer of molecules from low concentration to high concentration region.
  • thermal energy of the molecules.
  • activation energy of the molecules.
  • potential energy of the molecules.
Q.37

NSc/NPr is called the

  • psychrometric ratio
  • Lewis number
  • Sherwood number
  • Stantan number
Q.38

With lapse of time, the overhead composition of light component in case of batch distillation with constant reflux

  • increases
  • decreases
  • remains same
  • may increase or decrease ; depends on system.
Q.39

Lewis number, which is important in problems involving simultaneous heat and mass transfer, is the ratio of

  • mass diffusivity to momentum diffusivity.
  • thermal diffusivity to mass diffusivity.
  • momentum diffusivity to thermal diffusivity.
  • none of these.
Q.40

The recovery of pencillin from the acidified fermentation broth is done by

  • distillation
  • evaporation
  • absorption
  • liquid extraction
Q.41

Pick out the wrong statement pertaining to leaching.

  • Fine solids can not be leached in a Pachuka tank.
  • Door classifier can be used for leaching of coarse solids.
  • Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor.
  • Very high temperature is not needed for the leaching of sugar beet.
Q.42

In case of __________ distillation, a solvent is added to alter the relative volatility of the mixture to be separated.

  • molecular
  • azeotropic
  • extractive
  • flash.
Q.43

Water-ethyl alcohal solution can be concentrated (in respect of alcohal concentration) by __________ distillation.

  • atmospheric
  • vacuum
  • high pressure
  • none of these
Q.44

A binary mixture of benzene and cyclohexane is separated by

  • flash vaporisation
  • extractive distillation
  • solvent extraction
  • ordinary distillation
Q.45

Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular difusion, if

  • mass transfer is accompanied by reaction.
  • diffusion of A is in stagnant medium B.
  • molecular mean free path is high.
  • there is equimolar counter diffusion.
Q.46

The solvent used in liquid-liquid extraction should have __________ less than one.

  • selectivity
  • distribution co-efficient
  • both (a) and (b)
  • neither (a) nor (b).
Q.47

Decoction refers to the use of solvent

  • at ambient temperature
  • at its boiling point
  • in its vapor form
  • none of these
Q.48

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty ?

  • Grid tray tower
  • Perforated tray tower
  • Wetted wall tower
  • Bubble cap tower
Q.49

A liquid mixture containso-xylene,p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?

  • The mixture exhibits an azeotrope at 101.3 kPa.
  • The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10.
  • The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10.
  • The mixture contain optical isomers.
Q.50

McCabe-Thiele method

  • uses molal units for material and energy balance.
  • uses weight fractions to express liquid and vapour composition.
  • can use any type of units.
  • is more accurate than Ponchan-Savarit method.
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