MCQOPTIONS
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MCQOPTIONS
This section includes 590 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Water entrained by circulating air in cooling towers is termed as____________________? |
| A. | Drift |
| B. | Blow down |
| C. | Vapor load |
| D. | None of these |
| Answer» B. Blow down | |
| 52. |
Water entrained by circulating air in cooling towers is termed as________________? |
| A. | Drift |
| B. | Blow down |
| C. | Vapor load |
| D. | None of these |
| Answer» B. Blow down | |
| 53. |
Very tall packed towers are divided into series of beds to___________________? |
| A. | Reduce the overall pressure drop |
| B. | Avoid channelling |
| C. | Reduce liquid hold-up |
| D. | Avoid flooding |
| Answer» C. Reduce liquid hold-up | |
| 54. |
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) ? |
| A. | Increases pressure drop, increases surface area |
| B. | Increases pressure drop, decreases surface area |
| C. | Decreases pressure drop, increases surface area |
| D. | Decreases pressure drop, decreases surface area |
| Answer» D. Decreases pressure drop, decreases surface area | |
| 55. |
Use of packed towers for distillation is generally limited to the____________________? |
| A. | Small sizes |
| B. | Multi-component distillation |
| C. | High pressure operation |
| D. | Vacuum distillation |
| Answer» B. Multi-component distillation | |
| 56. |
Use of packed towers for distillation is generally limited to the__________________? |
| A. | Small sizes |
| B. | Multi-component distillation |
| C. | High pressure operation |
| D. | Vacuum distillation |
| Answer» B. Multi-component distillation | |
| 57. |
Use of natural draft cooling tower is practised, when the air has low ? |
| A. | Humidity |
| B. | Temperature |
| C. | Both A. & B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 58. |
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 _________________? |
| A. | Humidified with wet bulb temperature decreasing |
| B. | Humidified at constant wet bulb temperature |
| C. | Dehumidified |
| D. | None of these |
| Answer» B. Humidified at constant wet bulb temperature | |
| 59. |
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_________________? |
| A. | And humidified |
| B. | And dehumidified with increase in wet bulb temperature |
| C. | At the same relative humidity |
| D. | And dehumidified with decrease in wet bulb temperature |
| Answer» E. | |
| 60. |
Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be__________________? |
| A. | Cooled |
| B. | Humidified |
| C. | Both A. & B. |
| D. | Dehumidified |
| Answer» C. Both A. & B. | |
| 61. |
Unit operation involved in the prilling of urea is_____________________? |
| A. | Evaporation |
| B. | Drying |
| C. | Crystallisation |
| D. | Both B. and C. |
| Answer» E. | |
| 62. |
Unit of molal diffusivity is____________________? |
| A. | cm2/sec gm . mole |
| B. | gm moles/cm2 . sec |
| C. | gm moles/cm. sec |
| D. | gm moles/cm2. sec |
| Answer» D. gm moles/cm2. sec | |
| 63. |
Under conditions of flooding in packed tower, the gas pressure drop___________________? |
| A. | Decreases rapidly |
| B. | Increases rapidly |
| C. | Remain constant |
| D. | Is maximum |
| Answer» E. | |
| 64. |
Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around _____________ inches? |
| A. | 5 |
| B. | 30 |
| C. | 60 |
| D. | 100 |
| Answer» C. 60 | |
| 65. |
Tower diameter may be decreased by__________________? |
| A. | Using higher reflux ratio |
| B. | Use of increased tray spacing |
| C. | Increasing the liquid flow rate |
| D. | Increasing the vapour flow rate |
| Answer» C. Increasing the liquid flow rate | |
| 66. |
Total reflux in a distillation operation requires minimum____________________? |
| A. | Reboiler load |
| B. | Number of plates |
| C. | Condenser load |
| D. | All A., B. and C. |
| Answer» C. Condenser load | |
| 67. |
To remove all the moisture from a wet solid it requires exposure to _____________ air? |
| A. | Perfectly dry |
| B. | Highly humid |
| C. | High temperature |
| D. | None of these |
| Answer» B. Highly humid | |
| 68. |
To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate) ____________________? |
| A. | Increase both ‘G’ and ‘S’ |
| B. | Decrease both ‘G’ and ‘S’ |
| C. | Increase ‘S’ and decrease ‘G’ |
| D. | Increase ‘G’ and decrease ‘S’ |
| Answer» D. Increase ‘G’ and decrease ‘S’ | |
| 69. |
To get high tray efficiency___________________? |
| A. | Interfacial surface between liquid and gas phase should be large |
| B. | Time of contact between the two phases should be less |
| C. | Gas velocity should be very low |
| D. | Liquid entrainment should be severe |
| Answer» B. Time of contact between the two phases should be less | |
| 70. |
Though, theoretically the adsorption & desorption isotherms is expected to coincide but sometimes at least a part of the isotherms does not coincide and this phenomenon is known as adsorption hysteresis. In such cases, the desorption equilibrium pressure is ______________ that obtained for adsorption? |
| A. | Lower than |
| B. | Higher than |
| C. | Same as |
| D. | Either same or higher than |
| Answer» B. Higher than | |
| 71. |
The wetted wall tower is used to determine_________________________? |
| A. | Individual mass transfer co-efficient (M.T.C.) in gaseous system |
| B. | M.T.C. of individual components in a liquid-liquid system |
| C. | M.T.C. of liquid in liquid-gas system |
| D. | The overall M.T.C. of the system |
| Answer» B. M.T.C. of individual components in a liquid-liquid system | |
| 72. |
The wet and ‘dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be ______________ °C ? |
| A. | 25 |
| B. | > 25 |
| C. | < 25 |
| D. | – 25 |
| Answer» C. < 25 | |
| 73. |
The wet and ‘dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be ______________ °C? |
| A. | 25 |
| B. | > 25 |
| C. | < 25 |
| D. | – 25 |
| Answer» C. < 25 | |
| 74. |
The velocity, concentration and temperature boundary, for the boundary layer development on a flat plate during connective mass transfer will be same, if___________________? |
| A. | NSc = 1 |
| B. | NSc = NPr = NLe |
| C. | NPr = NLe |
| D. | NSc = NLe |
| Answer» C. NPr = NLe | |
| 75. |
The vapour pressure exerted by the moisture contained in a wet solid depends upon the____________________? |
| A. | Nature of the moisture |
| B. | Temperature |
| C. | Nature of the solid |
| D. | All A., B. and C. |
| Answer» E. | |
| 76. |
The value of „L/mG’ ratio for economical absorption operation ranges from _____________________? |
| A. | 0.5 to 0.8 |
| B. | 0.8 to 1.2 |
| C. | 1.25 to 2.0 |
| D. | 2.5 to 3.5 |
| Answer» D. 2.5 to 3.5 | |
| 77. |
The value of NA/(NA + NB) for steady state molecular diffusion of gas ‘A’ through nondiffusing gas ‘B’ is____________________? |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» B. ∞ | |
| 78. |
The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases ‘A’ and ‘B’ is____________? |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» C. 0.5 | |
| 79. |
The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around_________________? |
| A. | 1 |
| B. | 0.24 |
| C. | 3.97 |
| D. | 600 |
| Answer» B. 0.24 | |
| 80. |
The term “cooling range” in a cooling tower refers to the difference in the temperature of____________________? |
| A. | Cold water leaving the tower and the wet bulb temperature of the surrounding air |
| B. | Hot water entering the tower and the wet bulb temperature of the surrounding air |
| C. | Hot water entering the tower and the cooled water leaving the tower |
| D. | None of these |
| Answer» D. None of these | |
| 81. |
The term “approach” in a cooling tower refers to the difference in the temperature of the____________________? |
| A. | Cold water leaving the tower and the wet bulb temperature of the surrounding air |
| B. | Hot water entering the tower and the wet bulb temperature of the surrounding air |
| C. | Hot water entering and the cooled water leaving the cooling tower |
| D. | None of these |
| Answer» B. Hot water entering the tower and the wet bulb temperature of the surrounding air | |
| 82. |
The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the ______________ temperature? |
| A. | Dew point |
| B. | Wet bulb |
| C. | Dry bulb |
| D. | None of these |
| Answer» E. | |
| 83. |
The temperature of water cooled in cooling tower is always _________________ temperature of entering air? |
| A. | More than the wet bulb |
| B. | Less than the wet bulb |
| C. | Equal to the wet bulb |
| D. | Equal to the dry bulb |
| Answer» B. Less than the wet bulb | |
| 84. |
The suitable evaporator for concentration of foaming liquids is a ______________________ evaporator? |
| A. | Long tube |
| B. | Short tube |
| C. | Vacuum |
| D. | Falling film |
| Answer» B. Short tube | |
| 85. |
The solvent used in liquid-liquid extraction should have _______________ less than one? |
| A. | Selectivity |
| B. | Distribution co-efficient |
| C. | Both A. and B. |
| D. | Neither A. nor B. |
| Answer» E. | |
| 86. |
The solvent used in liquid extraction should not have high latent heat of vaporisation, because ______________________? |
| A. | The pressure drop and hence the pumping cost will be very high |
| B. | It cannot be recovered by distillation |
| C. | Its recovery cost by distillation may be prohibitively high |
| D. | It will decompose while recovering by distillation |
| Answer» D. It will decompose while recovering by distillation | |
| 87. |
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 |
| Answer» D. +ve | |
| 88. |
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 |
| Answer» D. +ve | |
| 89. |
The slope of 9-line is determined by the__________________? |
| A. | Reflux ratio |
| B. | Plate efficiency to be achieved |
| C. | Thermal condition of the feed |
| D. | Relative volatility |
| Answer» D. Relative volatility | |
| 90. |
The slope of 9-line is determined by the______________________? |
| A. | Reflux ratio |
| B. | Plate efficiency to be achieved |
| C. | Thermal condition of the feed |
| D. | Relative volatility |
| Answer» D. Relative volatility | |
| 91. |
The ‘shanks system’ of leaching (i.e., counter-current multiple contact leaching) is used for____________________? |
| A. | Recovery of tannis from the tree barks and woods |
| B. | Leaching sodium nitrate from Chilean nitrate bearing rock |
| C. | Both A. and B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 92. |
The Schmidt number which is defined as, μ/ρ D, is the ratio of the_____________________? |
| A. | Momentum diffusivity to the mass diffusivity |
| B. | Thermal diffusivity to the mass diffusivity |
| C. | Momentum diffusivity to the thermal diffusivity |
| D. | None of these |
| Answer» B. Thermal diffusivity to the mass diffusivity | |
| 93. |
The rough value of diffusion co-efficient of water vapor into air at 25°C may be about ______________ cm2/sec? |
| A. | 0.25 |
| B. | 2.5 |
| C. | 1.25 |
| D. | 0.0025 |
| Answer» B. 2.5 | |
| 94. |
The Reynolds number of the liquid was increased 100 fold for a laminar falling film used for gas-liquid contacting. Assuming penetrating theory is applicable, the fold increase in the mass transfer co-efficient (Kc) for the same system is_______________________? |
| A. | 100 |
| B. | 10 |
| C. | 5 |
| D. | 1 |
| Answer» C. 5 | |
| 95. |
The-relative volatility for separation of a non-ideal binary mixture by distillation should be ___________________? |
| A. | 0 |
| B. | 1 |
| C. | > 1 |
| D. | < 1 |
| Answer» D. < 1 | |
| 96. |
The relative volatility of a binary mixture at the Azeotropic composition is _______________________? |
| A. | 1 |
| B. | > 1 |
| C. | 0 |
| D. | ∞ |
| Answer» B. > 1 | |
| 97. |
The relative volatility of a binary mixture at constant temperature _________________ the total pressure? |
| A. | Decreases with increase in |
| B. | Increases with increase in |
| C. | Is independent of |
| D. | None of these |
| Answer» B. Increases with increase in | |
| 98. |
The relative saturation of an unsaturated mixture of gas and vapor is independent of the___________________? |
| A. | Nature of the vapor |
| B. | Temperature of the mixture |
| C. | Composition of the mixture |
| D. | None of these |
| Answer» E. | |
| 99. |
The relative saturation of a partially saturated mixture of vapour and gas can be increased by ________________ of the mixture? |
| A. | Reducing the total pressure |
| B. | Increasing the total pressure |
| C. | Reducing the temperature |
| D. | Both B. and C. |
| Answer» E. | |
| 100. |
The relative humidity of air decreases in-spite of an increase in the absolute humidity, when the____________________? |
| A. | Temperature rises |
| B. | Pressure rises |
| C. | Temperature falls |
| D. | Pressure falls |
| Answer» B. Pressure rises | |