Q.1

Sides of equilateral-triangular co-ordinates (on which ternary liquid system is plotted) represent

  • a pure component.
  • a binary mixture.
  • a ternary mixture.
  • partially miscible ternary system.
Q.2

Paper industry employs __________ driers.

  • cylinder
  • rotary
  • spray
  • fluidised bed
Q.3

Use of raschig rings in place of crushed stones as packing in packed beds (other things being same)

  • increases pressure drop, increases surface area.
  • increases pressure drop, decreases surface area.
  • decreases pressure drop, increases surface area.
  • decreases pressure drop, decreases surface area.
Q.4

For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of h2/ky.Cz is around

  • 0.60
  • 0.24
  • 1
  • 0.72
Q.5

Pick out the wrong statement:

  • Reboiler is not used in open steam distillation.
  • The separation of solutes of different molecular sizes in a liquid solution by use of a suitable membrane is called dialysis.
  • Freeze drying is used for the drying of fish.
  • Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux condition.
Q.6

The change in enthalpy per unit weight of adsorbed gas when adsorbed on gas free or "outgassed" adsorbent to from a definite concentration of adsorbate is called its

  • integral heat of adsorption.
  • heat of wetting.
  • differential heat of adsorption.
  • heat of normal condensation.
Q.7

The wetted wall tower is used to determine

  • individual mass transfer co-efficient (M.T.C.) in gaseous system.
  • M.T.C. of individual components in a liquid-liquid system.
  • M.T.C. of liquid in liquid-gas system.
  • the overall M.T.C. of the system.
Q.8

The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an __________ law.

  • exponential
  • parabolic
  • linear
  • cubic
Q.9

Prandtl number for water at 20°C is about

  • 7
  • 70
  • 0.7
  • 150.
Q.10

Make up water is supplied during cooling tower operation to compensate for water losses due to

  • evaporation
  • blowdown
  • entrainment
  • all (a), (b)&amp(c)
Q.11

In case of constant underflow extraction operation, the __________ at all solute concentration.

  • solids are drained to the same extent
  • ratio of the insoluble to solution is constant
  • both(a) & (b)
  • neither (a) nor (b)
Q.12

Water entrained by circulating air in cooling towers is termed as

  • drift
  • blow down
  • vapor load
  • none of these.
Q.13

The rate of mass transfer is not dependent upon the

  • degree of dispersion of one fluid in the other.
  • interfacial surface exposed between the phases.
  • both (a) & (b).
  • none of these.
Q.14

When the feed to a distillation column is a saturated liquid, slope of the feed line is

  • zero
  • unity
  • infinity
  • none of these
Q.15

In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when

  • saturated feed is not used.
  • an azeotrope forms.
  • the latent heat of vaporisation of the more and less volatile components are greatly different.
  • a total condenser is used.
Q.16

Critical humidity of a solid salt means the humidity

  • above which it will always become damp.
  • below which it will always stay dry.
  • both (a) and (b).
  • above Which it will always become dry and below which it will always stay damp.
Q.17

The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are

  • parallel
  • straight
  • both parallel and straight
  • neither parallel nor straight
Q.18

A slurry is to be dried to produce flaky solid. Which dryer would you recommend ?

  • Spray dryer
  • Drum dryer
  • Rotary dryer
  • Dielectric dryer
Q.19

Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent ?

  • Cooling and dehumidification.
  • Heating and dehumidification at almost constant wet bulb temperature.
  • Dehumidification with dry bulb temperature remaining constant.
  • None of these.
Q.20

The reciprocal of stripping factor is termed as

  • selectivity index
  • relative volatility
  • absorption factor
  • Murphree efficiency
Q.21

In paper industry, paper is dried in a __________ dryer.

  • tunnel
  • heated cylinder
  • conveyor
  • festoon
Q.22

The minimum number of theoretical plates is required for achieving a given separation in distillation column with

  • no reflux
  • total reflux
  • zero reflux ratio
  • minimum reflux ratio
Q.23

Weight of 1 m3 of humid air as compared to 1 m3 of dry air, under the same conditions, is

  • less
  • more
  • same
  • unpredictable
Q.24

Leaching of uranium ore and gold ore is done in

  • centrifugal extractor
  • Pachuka tanks
  • Bollman extractor
  • none of these
Q.25

Pick out the wrong statement.

  • The mole fraction of solute is directly proportional to the molality of a 'dilute' solution.
  • For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is nonlinear in the case of steady state unimolal unidirectional diffusion.
  • Azeotropes obey Raoult's law at all temperature.
  • The relative volatility of a binary mixture at the azeotropic composition is 1.
Q.26

In an absorption coloumn, the flooding velocity for random packing is __________ that for stacked/regular packing.

  • greater than
  • smaller than
  • equal to
  • either (a), or (b) ; depends on the type of packing
Q.27

The relation among various mass transfer co-efficients (M.T.C) for ideal gases is given by (where, Kc & Km are M.T.C. for equimolar counter diffusion with concentration & mole fraction respectively as the driving force. and, Kp = M.T.C. for diffusion of a gas through a stagnant inert gas with pressure as driving force.)

  • Kc = Kp = Km
  • Kc = Kp/RT = Km . RT/P
  • Kc = Kp . RT = Km . RT/p
  • none of these
Q.28

To get high tray efficiency

  • interfacial surface between liquid and gas phase should be large.
  • time of contact between the two phases should be less.
  • gas velocity should be very low.
  • liquid entrainment should be severe.
Q.29

Acm xcm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It tookseconds for the weight of the sheet to reduce to 1.kg. Anotherxx 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is

  • 1000
  • 1500
  • 2000
  • 2500
Q.30

__________ extractor uses centrifugal force for separating the two phases.

  • Treybal
  • Schiebel
  • Podbielniak
  • None of these
Q.31

Large scale drying of wheat is done in a __________ dryer.

  • fluidised bed
  • spouted bed
  • tray
  • vacuum rotary
Q.32

Leaching of sugar from sugar beets is done by

  • hot water
  • hexane
  • dilute H2SO4
  • lime water
Q.33

In an interphase mass transfer process, the lesser the solubility of a given solute in a liquid, the higher are the chances that the transfer process will be

  • liquid phase resistance-controlled.
  • gas phase resistance controlled.
  • impossible.
  • driven by a non-linear driving force.
Q.34

Ponchan-Savarit method analyses the fractional equipment based on

  • enthalpy balance only.
  • material balance only.
  • both enthalpy and material balances.
  • the assumption of constant molaloverflow.
Q.35

Blowdown in a cooling tower

  • means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities.
  • increases the scale forming tendencies of water.
  • is undesirable.
  • all (a), (b) & (c).
Q.36

With increase in temperature, the leaching rate increases because of the

  • increased diffusivity.
  • decreased viscosity of liquid.
  • both (a) and (b).
  • neither (a) nor (b).
Q.37

The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is

  • D/a
  • D/2a
  • proportional to D
  • dependent on the Reynolds number
Q.38

Pick out the wrong statement. Generally for physical adsorption, a gas of

  • higher molecular weight is adsorbed in preference to a gas of low molecular weight.
  • high critical temperature is adsorbed in preference to a gas of low critical temperature.
  • low volatility is adsorbed in preference to a gas of high volatility.
  • none of these.
Q.39

With increase in temperature, the rate of leaching increases, because the

  • diffusivity of solute increases.
  • viscosity of solvent decreases.
  • thermal conductivity of solute increases.
  • none of these.
Q.40

Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in terms of __________ humidity.

  • molal
  • relative
  • percentage
  • none of these
Q.41

In a binary distillation column, if the feed containsmole % vapour, the q line will have a slope of

  • 1.5
  • -0.6
  • -1.5
  • 0.6
Q.42

Azeotropic distillation is employed to separate

  • constant boiling mixture.
  • high boiling mixture.
  • mixture with very high relative volatility.
  • heat sensitive materials.
Q.43

The drying time between fixed moisture content within diffusion controlled 'falling rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid )

  • T
  • T
  • T2
  • T3
Q.44

As the reflux ratio decreases, the

  • separation becomes more efficient.
  • number of plates increases.
  • column diameter increases.
  • none of these.
Q.45

During constant rate period, the rate of drying decreases with the

  • decrease in air temperature
  • increase in air humidity
  • both (a) and (b)
  • neither (a) nor (b)
Q.46

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 'a', 'b' & 'c'.
Q.47

Pick out the wrong statement.

  • Mechanical agitation is required, if the system has low interfacial tension.
  • Seive tray towers are generally used for systems having low interfacial tension.
  • When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance.
  • Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers.
Q.48

At the boiling point of the liquid at the prevailing pressure, the saturated absolute humidity becomes

  • 1
  • 0
  • none of these
Q.49

Antibiotics are best handled in a

  • Podbielniak extractor.
  • sieve tray contractor.
  • rotating disc contactor.
  • pulsed column extractor.
Q.50

Acetic acid will be most economically separated from a dilute solution of acetic acid in water by

  • solvent extraction
  • continuous distillation
  • evaporation
  • absorption
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