__________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.
A. Dew point
B. Bubble point
C. Dry bulb temperature
D. Wet bulb temperature
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Advantage of continuous drying over batch drying is that the
A. Drying cost per unit weight of dried product is less
B. Product with more uniform moisture content is produced
C. Equipment size required is smaller
D. All of the above
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Channelling in a packed tower results from the
A. High pressure drop
B. Maldistribution of liquid
C. Non-uniformity of packing
D. Both B and C
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Pick out the wrong statement. Generally for physical adsorption, a gas of
A. Higher molecular weight is adsorbed in preference to a gas of low molecular weight
B. High critical temperature is adsorbed in preference to a gas of low critical temperature
C. Low volatility is adsorbed in preference to a gas of high volatility
D. None of these
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Dew point of a gas-vapour mixture
A. Increases with temperature rise
B. Decreases with temperature rise
C. Decreases with decrease in pressure
D. Increases with increase in pressure
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Which of the following is an undesirable property in a tower packing?
A. Large surface per unit volume
B. Large free cross-section
C. Low weight per unit volume
D. Large weight of liquid retained
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The most economical range of absorption factor is
A. 0 to 0.5
B. 0 to 3
C. 1.25 to 2
D. 5 to 15
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With increase in temperature, the leaching rate increases because of the
A. Increased diffusivity
B. Decreased viscosity of liquid
C. Both A and B
D. Neither A nor B
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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
A. Not possible in the second case unless vacuum is applied
B. Not possible in the second case unless high pressure is applied
C. More readily done in the second case compared to first one
D. None of these
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Leaching of coarse solid lumps is also termed as
A. Decoction
B. Dissolution
C. Percolation
D. Agitation and settling
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Critical humidity of a solid salt means the humidity
A. Above which it will always become damp
B. Below which it will always stay dry
C. Both A and B
D. Above Which it will always become dry and below which it will always stay damp
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The process employing desorption of the absorbed solute by a solvent is called
A. Elution
B. Osmosis
C. Reverse osmosis
D. Sublimation
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Degree of freedom for leaching and solvent extraction process is
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The reciprocal of stripping factor is termed as
A. Selectivity index
B. Relative volatility
C. Absorption factor
D. Murphree efficiency
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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.
A. Molal
B. Relative
C. Percentage
D. None of these
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Though, theoretically the adsorption & desorption isotherms is expected to coincide but sometimes at least a part of the isotherms does not coincide and this phenomenon is known as adsorption hysterisis. In such cases, the desorption equilibrium pressure is __________ that obtained for adsorption.
A. Lower than
B. Higher than
C. Same as
D. Either same or higher than
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Freundlich equation applies to the adsorption of solute from
A. Dilute solutions, over a small concentration range
B. Gaseous solutions at high pressure
C. Concentrated solutions
D. None of these
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The relative volatility of a binary mixture at the azeotropic composition is
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Packed column distillation is limited to the column __________ metres.
A. Height < 6
B. Diameter < 0.6
C. Both A & B
D. Neither A nor B
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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
A. D/a
B. D/2a
C. D. Dependent on the Reynolds number
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