Mass Transfer MCQs Archives

81. Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the

Packing may be crushed due to thermal expansion/contraction of the components of the equipments

Pressure drop in the equipment will be very high

Viscosity variation of the fluids may cause channeling/flooding

None of these

✅ The correct answer is option A.

82. Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature.

Less than

More than

Equal to

Either A or B; depends on the solid

✅ The correct answer is option A.

83. Drying of a wet solid under constant drying conditions means the exposure of the wet solid to the air of constant

Humidity

Velocity

Temperature

All of the above

✅ The correct answer is option D.

84. When the solvent dissolves very little of solute, then

Solvent of low latent heat of vaporisation should be used

Solvent of low freezing point should be used

Large quantity of solvent is required to extract the solute

Very small quantity of solvent is required

✅ The correct answer is option C.

85. Heat sensitive materials like certain pharmaceuticals and food stuffs can be dried in a/an __________ dryer.

Indirect tray

Spray

Freeze

None of these

✅ The correct answer is option C.

86. As the reflux ratio decreases, the

Separation becomes more efficient

Number of plates increases

Column diameter increases

None of these

✅ The correct answer is option B.

87. When the temperature and humidity of air is low, we usually use __________ draft cooling tower.

Natural

Forced

Induced

None of these

✅ The correct answer is option A.

88. A mixture of 10% C₆H₆ vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.

21.7

27.3

18.7

✅ The correct answer is option D.

89. For an absorber, both equilibrium and operating line will be straight for

Concentrated solution and non-isothermal operation

Dilute solution and non-isothermal operation

Dilute solution and isothermal operation

Concentrated solution and isothermal operation

✅ The correct answer is option C.

90. Packed column distillation is limited to the column __________ metres.

Height < 6

Diameter < 0.6

Both A & B

Neither A nor B

✅ The correct answer is option C.