71. If Rm is the minimum reflux ratio, the optimum reflux ratio may be around __________ Rm. September 7, 2025 by Admin 1.2 to 1.5 2.5 to 3 3 to 4 5 ✅ The correct answer is option A.
72. In distillation columns, the number of bubble caps per tray primarily depends upon the September 7, 2025 by Admin Allowable liquid velocity Allowable gas velocity Allowable gas and liquid velocities Feed composition ✅ The correct answer is option C.
73. Inside the distillation columns, the September 7, 2025 by Admin Highest temperatures is near the feed plate Driving force for the liquid flow is its weight Vapors are not always at their dew points All of the above ✅ The correct answer is option B.
74. Large scale usage of flash distillation is practised in September 7, 2025 by Admin Soap manufacturing Ammonia synthesis plant Polymerisation industry Petroleum refinning ✅ The correct answer is option D.
75. The surface renewal frequency in Danckwerts model of mass transfer is given by (KL: mass transfer co-efficient) September 7, 2025 by Admin √(KL².DA) KL².DA KL²/DA KL/DA² ✅ The correct answer is option A.
76. Boiling point diagram is not affected by the ambient September 7, 2025 by Admin Pressure Humidity Temperature Both B and C ✅ The correct answer is option D.
77. In case of an unsaturated mixture of gas and vapor, the percentage saturation is __________ its relative saturation. September 7, 2025 by Admin Lower than Higher than Equal to Either A or B, depends on the mixture composition ✅ The correct answer is option A.
78. The dew point of a saturated gas phase equals the __________ temperature. September 7, 2025 by Admin Gas Room Wet bulb None of these ✅ The correct answer is option A.
79. Under conditions of flooding in packed tower, the gas pressure drop September 7, 2025 by Admin Decreases rapidly Increases rapidly Remains constant Is maximum ✅ The correct answer is option D.
80. Which of the following is an undesirable property for an absorbing solvent? September 7, 2025 by Admin Low vapour pressure Low velocity Low freezing point None of these ✅ The correct answer is option D.