Q.1

The following plot gives the saturated humidity (He) versus temperature (T).Line joining (HTand (HTis the constant enthalpy line. Choose the correct one from among the alternatives A, B, C and D.

  • T1-Dew point temp; T2-Dry bulb temp; T3-Wet bulb temp.
  • T1-Dew point temp; T2-Wet bulb temp; T3-Dry bulb temp.
  • T1-Wet bulb temp; T2-Dry bulb temp; T3-Dew point temp.
  • T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp.
Q.2

For the flow of gases through a capillary, with increase in temperature, the permeability __________ as per Knudsen law.

  • increases
  • decreases
  • remains same
  • either (a) or (b); depends on the gas
Q.3

Tower diameter may be decreased by

  • using higher reflux ratio.
  • use of increased tray spacing.
  • increasing the liquid flow rate.
  • increasing the vapour flow rate.
Q.4

Which of the following can be calculated theoretically using steam table and Dalton's law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known ?

  • Dew point
  • Humidity ratio
  • Wet bulb temperature
  • None of these
Q.5

Pick out the wrong statement

  • A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity.
  • When water is cooled from 80 to 70°C by exposure to the air with a wet bulb temperature of 60°C, then both the approach & the range would be 10°C.
  • For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature & adiabatic cooling lines are the same.
  • Relative saturation of unsaturated mixture of water vapor & air can not be increased by either reducing the mixture temperature or by increasing the total pressure.
Q.6

Molecular diffusivity of a liquid

  • increases with temperature.
  • decreases with temperature.
  • may increase or decrease with temperature.
  • is independent of temperature.
Q.7

Cox chart, which is useful in the design of distillation column particularly for petroleum hydrocarbons, is a plot of (where, P = vapor pressure, T = temperature)

  • log P vs . T
  • log P vs. log T
  • T vs . P
  • P vs . log T
Q.8

With increase in temperature, the mutual solubility of two liquids

  • increases
  • decreases
  • remains unchanged
  • decreases exponentially
Q.9

Experimental determination of __________ is done by wetted wall column method.

  • diffusion co-efficient
  • mass transfer co-efficient
  • NTU
  • none of these
Q.10

The individual mass transfer co-efficients (moles/m2 . s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.The slope of the equilibrium line isWhich of the following resistance (s) is (are) controlling ?

  • liquid side
  • gas side
  • interfacial
  • both liquid and gas side
Q.11

Mass transfer co-efficient is directly proportional to DAB according to the __________ theory.

  • film
  • penetration
  • surface-renewal
  • none of these
Q.12

Drying of a solid involves __________ transfer.

  • only heat
  • only mass
  • both heat and mass
  • none of these
Q.13

To remove all the moisture from a wet solid it requires exposure to __________ air.

  • perfectly dry
  • highly humid
  • high temperature
  • none of these
Q.14

The most efficient cooling tower out of the following is

  • induced draft
  • forced draft
  • natural draft
  • atmospheric
Q.15

Rayleigh's equation applies to __________ distillation.

  • continuous
  • steam
  • differential
  • flash
Q.16

The wet and 'dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be __________ °C.

  • 25
  • > 25
  • < 25
  • - 25
Q.17

Henry's law states that the

  • partial pressure of a component over a solution is proportional to its mole fraction in the liquid.
  • partial pressure of a component over a solution is proportional to the mole fraction in the vapour.
  • vapour pressure is equal to the product of the mole fraction and total pressure.
  • partial pressure is equal to the product of the mole fraction and total pressure.
Q.18

The unit of volumetric diffusivity is

  • cm2/sec
  • cm/sec
  • cm3/sec
  • cm2/sec2
Q.19

For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.

  • binary mixture is represented by the apex
  • binary mixture is represented by any point inside
  • ternery mixture is represented by the sides
  • pure component is represented by the apex.
Q.20

Mechanism of moisture removal in case of freeze drying of food stuff is by

  • evaporation
  • sublimation
  • dehydration
  • adsorption
Q.21

The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.

  • composition
  • temperature
  • total pressure
  • all (a), (b) and (c)
Q.22

Sodium bicarbonate is produced during soda ash manufacture using a __________ tower.

  • plate
  • baffle
  • packed
  • none of these
Q.23

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 liquid-solid diffusion systems.
Q.24

Which is not concerned directly with mass transfer ?

  • Schmidt number
  • Sherwood number
  • Lewis relationship
  • Froude number
Q.25

Powdery materials can be guarded against caking tendency on storage by

  • providing irregular grain size.
  • providing minimum percentage of voids.
  • having maximum possible points of contact.
  • none of these.
Q.26

Which of the following is considered equivalent to one theoretical stage in Mc-Cabe Thiele's method ?

  • Partial condenser
  • Total condenser
  • Reboiler
  • Both (b) and (c)
0 h : 0 m : 1 s