1. Dry bulb temperature of the gas is __________ the wet bulb temperature.
Correct : B. More than
2. __________ column is used in gas absorption process.
Correct : D. Packed
3. The equilibrium liquid composition compared to the vapor composition in case of Azeotropic mixture is
Correct : C. Same
4. The diffusion co-efficient in m2
/s. of acetic acid in benzene (liquid in liquid) is
Correct : A. 2.09 × 10-4
5. Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled
Correct : D. And dehumidified with decrease in wet bulb temperature
6. The 'shanks system' of leaching (i.e., counter-current multiple contact leaching) is used for
Correct : C. Both (A) and (B)
7. The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around
Correct : A. 1
8. Which of the following employs an accessory known as 'drift eliminator'?
Correct : B. Mechanical draft cooling tower
9. Dew point of an air-water vapor mixture
Correct : D. All 'a', 'b' & 'c'
10. The term "approach" in a cooling tower refers to the difference in the temperature of the
Correct : A. Cold water leaving the tower and the wet bulb temperature of the surrounding air
11. The relation, Sc = Pr = 1, is valid, when the mechanism of __________ transfer is same.
Correct : A. Heat and mass
12. McCabe-Thiele method
Correct : A. Uses molal units for material and energy balance
13. If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent.
Correct : B. > 100
14. Humid volume, at a given temperature is a/an __________ function of humidity.
Correct : C. Linear
15. If the specific heats of a gas and a vapor are 0.2KJ/Kg.°K and 1.5 KJ/Kg.°K respectively, and the humidity is 0.01; the humid heat in KJ/°Kg. is
Correct : D. 0.215
16. Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.
Correct : B. More than
17. In case of __________ distillation, a solvent is added to alter the relative volatility of the
mixture to be separated.
Correct : C. Extractive
18. Pick out the wrong statement.
Correct : C. Diameter of randomly packed tower is normally more than 1.2 metres
19. Moisture contained by a substance in excess of the equilibrium moisture is called the __________ moisture.
Correct : B. Free
20. Which of the following is an undesirable characteristic for the solvent used in gas absorption?
Correct : D. None of these
21. Hypersorption refers to a __________ process.
Correct : D. Moving bed adsorption
22. Drying of refractory is normally carried out in a __________ dryer.
Correct : D. Truck/tunnel
23. For the same feed, feed quality and separation (in a distillation column), with the increase
of total pressure, the number of ideal plates will
Correct : A. Increase
24. In case of liquids, the binary diffusivity is proportional to (where, T = temperature)
Correct : A. T
25. A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?
Correct : A. The mixture exhibits an azeotrope at 101.3 kPa
26. The relative saturation of an unsaturated mixture of gas and vapor is independent of the
Correct : D. None of these
27. In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
Correct : A. Area between operating line and 45° diagonal x-y diagram
28. Advantage of continuous drying over batch drying is that the
Correct : D. All 'a', 'b' & 'c'
29. Which of the following assumes constant molal vaporisation and overflow?
Correct : A. McCabe-Thiele method
30. An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively. The humidity of air sample expressed as kg of water vapour/kg of dry air is:
Correct : D. 0.152
31. Which of the following binary systems is an example of a maximum boiling azeotrope?
Correct : A. Water-hydrochloric acid
32. For an absorber, both equilibrium and operating line will be straight for
Correct : C. Dilute solution and isothermal operation
33. Channelling is most severe
Correct : A. In towers packed with stacked packing
34. Penetration model (theory) for mass transfer was enunciated by
Correct : C. Higbie
35. Pick out the correct statement.
Correct : A. Bound moisture is removed during constant rate drying period
36. Milk is dried usually in a __________ dryer.
Correct : B. Spray
37. Extraction of coffee from its seed is done by
Correct : B. Leaching
38. Unit of molal diffusivity is
Correct : C. gm moles/cm. sec
39. When the liquid phase and vapour phase of a binary system obeys Raoult's and Dalton's law respectively, the relative volatility is the ratio of
Correct : A. Vapour pressure of component A to that of component B
40. In case of non-ideal gases and liquids, the molal diffusivity
Correct : C. Is independent of pressure
41. Flooding in a column results due to
Correct : A. High pressure drop
42. Which of the following is a suitable absorbent for removal of H2S from natural gas?
Correct : B. Monoethanolamine (MEA)
43. Raoult's law is applicable to the
Correct : A. Ideal solutions
44. Humid volume is the total volume in m3 of 1 kg of
Correct : C. Gas plus its accompanying vapour at 1 atm. and gas temperature
45. Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.
Correct : A. Rotary
46. Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation.
Correct : D. Simple
47. Pick out the system with minimum boiling azeotrope at 1 atm.
Correct : B. Ethyl alcohol-water
48. Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and
Correct : A. Humidified with wet bulb temperature decreasing
49. The film penetration model of mass transfer was enunciated by
Correct : B. Toor and Marcello
50. Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maxi-mum equilibrium moisture?
Correct : C. Bamboo
51. (NRe . NSc) is termed in mass transfer operation as the __________ number.
Correct : C. Peclet
52. At a given equilibrium pressure, with increase in temperature, the concentration of adsorbed gas on solid adsorbent
Correct : B. Decreases
53. With lapse of time, the overhead composition of light component in case of batch distillation with constant reflux
Correct : B. Decreases
54. HETP is numerically equal to HTU, only when the operating line
Correct : C. And equilibrium lines are parallel
55. The operation involved when the soluble material is largely on the surface of an insoluble solid and is merely washed off by the solvent is called
Correct : C. Elutriation or elution
56. __________ number indicates the ratio of the rates of the heat and mass transfer incase of a
cooling tower.
Correct : C. Lewis
57. The recovery of penicillin from the acidified fermentation broth is done by
Correct : D. Liquid extraction
58. Drift in a cooling tower is
Correct : A. The water entrained by the circulating air
59. In McCabe-Thiele method, at infinite reflux ratio
Correct : A. The overhead product is minimum
60. Gaseous diffusivity at atmospheric pressure is of the order of __________ cm2/second.
Correct : A. 1
61. Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be
Correct : B. > 1
62. Pick out the wrong statement.
Correct : D. Vander wall adsorption is also called chemisorption
63. Molarity is defined as the number of gm moles of solute per __________ of solvent.
Correct : A. Litre
64. If Rm is the minimum reflux ratio, the optimum reflux ratio may be around __________ Rm.
Correct : A. 1.2 to 1.5
65. Adsorption is a unit operation which generally involves __________ systems.
Correct : C. Fluid-solid
66. Surface renewal model of mass transfer was enunciated by
Correct : C. Danckwerts
67. Agitator is provided in a crystalliser for
Correct : D. All (A), (B) and (C)
68. Which of the following adsorbent is used to decolourise yellow glycerine?
Correct : D. Activated carbon
69. Lewis number, which is important in problems involving simultaneous heat and mass transfer, is the ratio of
Correct : B. Thermal diffusivity to mass diffusivity
70. Binary distillation involves the mass transfer by __________ at the gas-liquid interface.
Correct : D. A counter diffusion at an almost equal molar rate
71. Corresponding to Nusselt number in heat transfer, the dimensionless group in mass
transfer is the __________ number.
Correct : A. Sherwood
72. Sand is dried in foundries in a _________drier.
Correct : B. Fluidised bed
73. Cox chart is useful in the design of
Correct : A. Distillation column
74. Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are:
Correct : C. 9
75. In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X,
where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer.
Correct : D. No amount of C is tr
76. Pick out the wrong statement pertaining to leaching.
Correct : A. Fine solids cannot be leached in a Pachuca tank
77. Azeotropism for ethyl alcohol-water system disappears by
Correct : B. Decreasing pressure
78. Ordinary diffusion process is also called __________ diffusion.
Correct : C. Concentration
79. The falling rate period in the drying of a solid is characterised by
Correct : B. Increasing temperatures both on the surface and within the solid
80. Decoction refers to the use of solvent
Correct : B. At its boiling point
81. Schmidt number and Lewis number for pure air at atmospheric conditions are respectively
Correct : A. < 1 and ≈ 1
82. Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower.
Correct : A. Wetted wall
83. Pick out the correct statement.
Correct : D. All (A), (B) and (C)
84. The solvent used in liquid-liquid extraction should have __________ less than one.
Correct : D. Neither (A) nor (B)
85. Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the
Correct : A. Mass transfer co-efficient
86. Pick out the wrong statement.
Correct : C. Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
87. Which of the following equipments is not used for liquid dispersion?
Correct : D. Agitated vessels
88. The rough value of diffusion co-efficient of water vapor into air at 25°C may be about __________ cm2/sec.
Correct : A. 0.25
89. Molecular diffusion is caused by the
Correct : B. Thermal energy of the molecules
90. Liquid diffusivity is of the order of __________ cm2
/second.
Correct : C. 10-5 to 10-6
91. The diffusivity, DAB (for component A diffusing in B) is equal to the diffusivity DBA (for
component B diffusing in A) for a binary mixture of
Correct : C. Ideal gases
92. Can a cooling tower cool water below the wet bulb temperature of inlet air?
Correct : B. No
93. The expression, ln(F/W) = ∫ xF xW [dx/y* - x)] is
Correct : A. Differential distillation equation
94. Wetted wall tower experiment determines the
Correct : C. Mass transfer co-efficient
95. Condensation of a vapour-gas mixture just begins, when (where, p = partial pressure of the vapour P = vapour pressure of the liquid).
Correct : A. p = P
96. If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are:
Correct : C. Both (A) & (B)
97. JD factor for mass transfer is a function of Reynolds number. Mass transfer by molecular diffusion from a single drop to surrounding still air is given by
Correct : A. Nsh = 2
98. In liquid-liquid extraction, the number of phases at plait point is
Correct : A. 1
99. Molecular sieves are porous
Correct : C. Synthetic zeolites crystals/metal alumino-silicates
100. Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off __________ °C.