2. Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant.
Correct : A. Agitated vessel
3. Schmidt number is given by
Correct : A. µ/ρDAB
4. Pick out the correct statement.
Correct : D. None of these
5. Fenske equation determines the
Correct : C. Minimum number of theoretical plates
6. If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively
Correct : B. [RD/(RD + 1)], [xD/(xD + 1)]
7. Which of the following equipments is not used for gas dispersion?
Correct : D. Spray towers
8. __________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids.
Correct : C. Plate
9. When adsorption hysteresis is observed, the desorption equilibrium pressure is __________ that obtained by adsorption.
Correct : A. Always lower than
10. On addition of solute in the solvent, the __________ of the solution decreases.
Correct : D. Both (B) and (C)
11. Extraction of penicillin employs a __________ extraction column.
Correct : A. Centrifugal
12. Which of these columns incurs the lowest pressure drop?
Correct : A. Packed column (with stacked packing)
13. 'Absorption with chemical reaction' is involved in the removal of
Correct : A. Carbon dioxide from gaseous stream using alkaline solution
14. Which of the following mixtures does not form an azeotrope at atmospheric pressure?
Correct : D. None of these
15. In batch distillation with constant reflux, overhead product composition __________ with time.
Correct : B. Decreases
16. McCabe-Thiele method of binary distillation does not assume that the
Correct : D. None of these
17. Which of the following same diameter columns gives lowest pressure drop per unit height?
Correct : C. Packed column (stacked)
18. Absorption factor method is used to calculate the number of ideal stages, when
Correct : C. Both operating and equilibrium lines are parallel
19. Entrainer used in Azeotropic distillation should
Correct : A. Form a low boiling azeotrope with one of the constituents of the mixture
20. A plait point is the point on the solubility curve, where the tie line reduces to a point. What is the number of plait point for a ternary system containing two pairs of partially miscible liquids?
Correct : A. Zero
21. For the same process conditions, the reflux ratio of an unlagged distillation column
Correct : B. Increases in winter
22. Minimum possible diameter of a packed column is decided mainly by the
Correct : A. Flooding
23. Ponchon-Savarit method analyses the fractional equipment based on
Correct : C. Both enthalpy and material balances
24. Dryer widely used in a textile industry is __________ dryer.
Correct : C. Conveyor
25. Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty?
Correct : D. Wetted wall column
26. In a binary system, separation is very efficient, when the relative volatility is
Correct : B. > 1
27. The following plot gives the saturated humidity (He) versus temperature (T).Line joining (H1, T1) and (H2, T2) is the constant enthalpy line. Choose the correct one from among the alternatives A, B, C and D.
Correct : D. T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp
28. Channelling in a packed tower results from the
Correct : D. Both (B) and (C)
29. Which of the following adsorbent is used in the refining of sugar?
Correct : A. Bone charcoal
30. With increase in pressure, the relative volatility for a binary system
Correct : B. Decreases
31. When the liquid over a plate is of uniform concentration, then
Correct : C. Murphree efficiency = point efficiency
32. Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when
Correct : D. One of the liquid components has very high affinity towards the solvent
33. A good solvent used for absorption should not have very high
Correct : D. All (A), (B) & (C)
34. An example of elution is
Correct : A. Separation of uranium oxide from its ore by H2SO4 in a Pachuca tank
35. The term "cooling range" in a cooling tower refers to the difference in the temperature of
Correct : C. Hot water entering the tower and the cooled water leaving the tower
36. If the amount of the steam used in steam distillation is increased, the temperature of distillation
Correct : B. Decreases
37. Rate of leaching increases with increasing
Correct : A. Temperature
38. With increase in gas rate, the number of transfer units, NtoG, for a fixed degree of absorption by a fixed amount of solvent
Correct : A. Increases
39. Heat load in a cooling tower
Correct : C. Both (A) & (B)
40. Separation of two or more components of a liquid solution cannot be achieved by
Correct : C. Absorption
41. For __________ drying, the effects of velocity, temperature and humidity of the gas and the
thickness of the solid are the same.
Correct : C. Both (A) and (B)
42. In continuous distillation, the internal reflux ratio (Ri) and the external reflux ratio (Re) are related as
Correct : D. Ri = Re/(1 + Re)
43. Deaeration (removal of O2) of water is done by
Correct : C. Ion-exchange
44. For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because
Correct : A. Water has a high latent heat of evaporation
45. Dew point of a gas-vapour mixture
Correct : C. Decreases with decrease in pressure
46. If moisture content of solid on dry basis is X, then the same on wet basis is
Correct : A. X/(X + 1)
47. __________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gas-vapor mixture.
Correct : B. Wet bulb
48. The-relative volatility for separation of a non-ideal binary mixture by distillation should be
Correct : C. > 1
49. In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapour, because
Correct : C. Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition
50. Which of the following unit operations makes use of Thiele-Geddes equation?
Correct : D. Multi-component distillation
51. Gaseous diffusion co-efficient increases with increase in the
Correct : B. Temperature
52. Sides of equilateral-triangular co-ordinates (on which ternary liquid system is plotted)
represent
Correct : B. A binary mixture
53. The rate of mass transfer is not dependent upon the
Correct : D. None of these
54. Air at a particular humidity is heated in a furnace. The new dew point
Correct : B. Increases
55. The rate of solid-liquid extraction is limited by the
Correct : D. All 'a', 'b' & 'c'
56. In case of gases, the binary diffusivity is proportional to (where, P = pressure).
Correct : B. 1/P
57. One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult's law is obeyed, then changing the feed composition would effect
Correct : C. The fraction vaporised but not the product composition
58. What is the reflux ratio at total reflux?
Correct : B. Infinity
59. The operating line for an absorber is curved, when plotted in terms of
Correct : C. Partial pressure
60. Which of the following is the most suitable for extraction in a system having very low
density difference?
Correct : B. Centrifugal extractor
61. (NSh/NRe.NSc) is termed in mass transfer operation as the
Correct : A. Stanton number
62. In the desorption of highly soluble gas from the liquid, the main resistance will be in the __________ phase.
Correct : B. Liquid
63. Positive deviation from Raoult's law means a mixture whose total pressure is
Correct : A. Greater than that computed for ideality
64. Flooding results in
Correct : B. Low tray efficiency
65. At minimum reflux ratio for a given separation
Correct : B. Number of plates is infinity
66. An ideal tower packing should not
Correct : D. Hold up large amount of liquid in the packing
67. Diffusion in concentrated solutions differs from that in dilute solutions, because of the change in the __________ with the concentration of the solution.
Correct : C. Both 'a '& 'b'
68. Make up water is supplied during cooling tower operation to compensate for water losses due to
Correct : D. All (A), (B) & (C)
69. The dimension of diffusivity is same as that of the
Correct : C. Kinematic viscosity
70. As the reflux ratio in a distillation column is increased from the minimum, the
Correct : C. Total cost first decreases and then increases
71. Fenske-Underwood equation used for calculating the minimum number of theoretical
plates in distillation column is valid for
Correct : D. All (A), (B) and (C)
72. Solvent used in extractive distillation
Correct : B. Forms a low boiling azeotrope
73. When the feed to a distillation column is a saturated liquid, slope of the feed line is
Correct : C. Infinity
74. The absorption factor is defined as (where, L = liquid flow rate, G = gas flow rate and, m = slope of the equilibrium line).
Correct : A. L/mG
75. Chemisorption (chemical adsorption) is
Correct : C. An irreversible phenomenon
76. 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.
Correct : D. 18.7
77. Inside the distillation column, the
Correct : A. Driving force for the vapour flow is the pressure drop
78. Dry bulb temperature of unsaturated air is more than its __________ temperature.
Correct : C. Both 'a' & 'b'
79. Boiling point diagram is not affected by the ambient
Correct : D. Both (B) and (C)
80. Total reflux in a distillation operation requires minimum
Correct : B. Number of plates
81. Inside the distillation columns, the
Correct : B. Driving force for the liquid flow is its weight
82. An Azeotropic mixture is a __________ mixture.
Correct : C. Constant boiling point
83. The change in enthalpy per unit weight of adsorbed gas when adsorbed on gas free or "outgassed" adsorbent to from a definite concentration of adsorbate is called its
Correct : A. Integral heat of adsorption
84. The diffusivity (D) in a binary gas mixture is related to the temperature (T) as
Correct : C. D ∝ T 1.5
85. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = __________
Correct : A. 1
86. At a fixed total pressure, humidity depends only on the
Correct : A. Partial pressure of vapour in the mixture
87. In extractive distillation, solvent is
Correct : A. Added to alter the relative volatility of the mixture
88. Pick out the wrong statement.
Correct : C. Azeotropes obey Raoult's law at all temperature
89. During drying operation, it is easier to remove the __________ moisture.
Correct : C. Unbound
90. Which of the following quantities need not be fixed before starting the design of a cocurrent absorber?
Correct : B. Flow rate of entering liquid
91. Which of the following parameters remains almost constant during adiabatic saturation of unsaturated air?
Correct : C. Wet bulb temperature
92. In an absorber, HETP does not vary with the
Correct : D. None of these
93. Leaching of sugar from sugar beets is done by
Correct : A. Hot water
94. In case of liquid-liquid binary diffusion, diffusivity of one constituent into another is not dependent on the
Correct : D. None of these
95. When the temperature and humidity of air is low, we usually use __________ draft cooling tower.
Correct : A. Natural
96. Water-ethyl alcohol solution can be concentrated (in respect of alcohol concentration) by __________ distillation.
Correct : B. Vacuum
97. In an interphase mass transfer process, the lesser the solubility of a given solute in a liquid, the higher are the chances that the transfer process will be
Correct : B. Gas phase resistance controlled
98. Percentage saturation is __________ the relative saturation.
Correct : A. Always smaller than
99. If a1 and a2 are the relative volatilities when the pressure in the distillation column is 1 and 2 atm respectively. Pick out the correct statement.
Correct : D. None of these
100. In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor.