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.
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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.
For the flow of gases through a capillary, with increase in temperature, the permeability __________ as per Knudsen law.
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increases -
decreases -
remains same -
either (a) or (b); depends on the gas
Tower diameter may be decreased by
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using higher reflux ratio. -
use of increased tray spacing. -
increasing the liquid flow rate. -
increasing the vapour flow rate.
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 ?
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Dew point -
Humidity ratio -
Wet bulb temperature -
None of these
Pick out the wrong statement
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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.
Molecular diffusivity of a liquid
-
increases with temperature. -
decreases with temperature. -
may increase or decrease with temperature. -
is independent of temperature.
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)
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log P vs . T -
log P vs. log T -
T vs . P -
P vs . log T
With increase in temperature, the mutual solubility of two liquids
-
increases -
decreases -
remains unchanged -
decreases exponentially
Experimental determination of __________ is done by wetted wall column method.
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diffusion co-efficient -
mass transfer co-efficient -
NTU -
none of these
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 ?
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liquid side -
gas side -
interfacial -
both liquid and gas side
Mass transfer co-efficient is directly proportional to DAB according to the __________ theory.
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film -
penetration -
surface-renewal -
none of these
Drying of a solid involves __________ transfer.
-
only heat -
only mass -
both heat and mass -
none of these
To remove all the moisture from a wet solid it requires exposure to __________ air.
-
perfectly dry -
highly humid -
high temperature -
none of these
The most efficient cooling tower out of the following is
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induced draft -
forced draft -
natural draft -
atmospheric
Rayleigh's equation applies to __________ distillation.
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continuous -
steam -
differential -
flash
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.
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25 -
> 25 -
< 25 -
- 25
Henry's law states that the
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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.
The unit of volumetric diffusivity is
-
cm2/sec -
cm/sec -
cm3/sec -
cm2/sec2
For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.
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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.
Mechanism of moisture removal in case of freeze drying of food stuff is by
-
evaporation -
sublimation -
dehydration -
adsorption
The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.
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composition -
temperature -
total pressure -
all (a), (b) and (c)
Sodium bicarbonate is produced during soda ash manufacture using a __________ tower.
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plate -
baffle -
packed -
none of these
Steady state equimolal counter diffusion is encountered in
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separation of a binary mixture by distillation. -
absorption of NH3 from air by water. -
all liquid-liquid diffusion systems. -
all liquid-solid diffusion systems.
Which is not concerned directly with mass transfer ?
-
Schmidt number -
Sherwood number -
Lewis relationship -
Froude number
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.
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)