Mass Transfer - Study Mode

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[#486] The slope of the operating line for a single component co-current absorber when plotted in terms of mole ratio units is

(A) 0

(B) ∞

(C) -ve

(D) +ve

Correct Answer

[#487] For the same process conditions, the reflux ratio of an unlagged distillation column

(A) Decreases in winter

(B) Increases in winter

(C) Increases in summer

(D) None of these

Correct Answer

(B) Increases in winter

[#488] The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is

(A) Natural draft cooling tower

(B) Induced draft cooling tower

(C) Spray chamber

(D) None of these

Correct Answer

[#489] Pick out the wrong statement

(A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity

(B) 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

(C) For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature & adiabatic cooling lines are the same

(D) 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

(E) Co-current absorbers are usually used, when the gas to be dissolved in the liquid is a pure substance

(F) In case of gas absorption, HETP is equal to HTU, when both the operating line & the equilibrium lines are parallel

(G) Hatta number is important in case of gas absorption with chemical reaction

(H) In actual practice, absorption is an en-dothermic process, while stripping is an exothermic process

Correct Answer

(D) 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
(H) In actual practice, absorption is an en-dothermic process, while stripping is an exothermic process

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

(A) Atmospheric

(B) Vacuum

(C) High pressure

(D) None of these

Correct Answer

(B) Vacuum