|
1) Pick out the wrong statement pertaining to the cooling towers ? a. In case of induced draft cooling tower, the fan is placed at the top of the tower b. Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air c. A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low d. Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature
|
||||
|
2) Pick out the wrong statement ? a. In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy b. With increase in pressure, the solubility of gases in solvent increases at a fixed temperature c. Decrease in Murphree plate efficiency is an indication of entrainment in distillation column d. The capacity of a distillation column is maximum at total reflux
|
||||
|
3) Alcohol is dehydrated using _______________________ distillation? a. Extractive b. Azeotropic c. Steam d. Molecular
|
||||
|
4) Water entrained by circulating air in cooling towers is termed as____________________? a. Drift b. Blow down c. Vapor load d. None of these
|
||||
|
5) Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________? a. Sherwood number in mass transfer is analogous to Nusselt number in heat transfer b. Prandtl number in heat transfer is analogous to Schmidt number in mass transfer c. Reynolds number in mass transfer is analogous to Grashoff number in heat transfer d. Reynolds number remains the same in both heat and mass transfer
|
||||
|
6) Pick out the wrong statement. Raoult’s law does not apply, when the______________________? a. Size of component molecules are not equal b. Attractive forces between like and unlike molecules in the solution are approximately equal c. Component molecules are non-polar d. Chemical combination or molecular association between unlike molecules takes place in the formation of solution
|
||||
|
7) 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
|
||||
|
8) Plate efficiency in a distillation column is reduced due to the ______________________ of liquid? a. Entrainment b. Foaming c. Weeping & dumping d. All A., B. & C.
|
||||
|
9) Blowdown in a cooling tower____________________? a. Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities b. Increases the scale forming tendencies of water c. Is undesirable d. All A., B. & C.
|
||||
|
10) In extraction, as the temperature increases, the area of heterogeneity (area covered by binodal curve)________________? a. Decreases b. Increases c. Remains unchanged d. None of these
|
||||
|
11) Rayleigh’s equation applies to _________________ distillation? a. Continuous b. Steam c. Differential d. Flash
|
||||
|
12) The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2/m3) ? a. 500 b. 1200 c. 900 d. 800
|
||||
|
13) For a binary mixture with low relative volatility________________? a. Use steam distillation b. Use molecular distillation c. Use high pressure distillation d. An azeotrope may be formed during distillation
|
||||
|
14) The Hatta number is important in______________________? a. Multi-component distillation b. Binary distillation c. Gas absorption without chemical reaction d. Gas absorption with chemical reaction
|
||||
|
15) A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))_____________? a. M(Xo – XF) b. M(Xo/XF) c. M ln(Xo/XF) d. MXo ln(Xo/XF)
|
||||
|
16) Freundlich equation applies to the adsorption of solute from_____________________? a. Dilute solutions, over a small concentration range b. Gaseous solutions at high pressure c. Concentrated solutions d. None of these
|
||||
|
17) 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
|
||||
|
18) The dew point of an unsaturated gas-vapor mixture does not depend upon the ____________________ of the mixture? a. Composition b. Temperature c. Total pressure d. All A., B. and C.
|
||||
|
19) The critical moisture content in case of drying indicates the _______________ rate period? a. Beginning of falling b. Beginning of constant c. End of falling d. None of these
|
||||
|
20) Separation of two volatile liquids by distillation makes use of their________________________? a. Selectivity b. Relative volatility c. Solubility d. Density difference
|
||||
|
21) The minimum liquid rate to be used in an absorber corresponds to an operating line_______________________? a. Of slope = 1 b. Of slope = 0.1 c. Tangential to the equilibrium curve d. None of these
|
||||
|
22) Powdery materials can be guarded against caking tendency on storage by_________________? a. Providing irregular grain size b. Providing minimum percentage of voids c. Having maximum possible points of contact d. None of these
|
||||
|
23) In case of physical adsorption, the difference between heat of adsorption and heat of normal condensation is__________________? a. Equal to the heat of formation of surface compound b. Equal to the heat of wetting c. Zero d. Called integral heat of adsorption
|
||||
|
24) Leaching of uranium ore and gold ore is done in________________________? a. Centrifugal extractor b. Pachuca tanks c. Bollman extractor d. None of these
|
||||
|
25) For a ternary mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a _______________ of the equilateral triangular co-ordinates? a. Binary mixture is represented by the apex b. Binary mixture is represented by any point inside c. Ternary mixture is represented by the sides d. Pure component is represented by the apex
|
||||
|
26) 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
|
||||
|
27) In a gas-liquid absorption column, for obtaining the maximum absorption efficiency____________________? a. Liquid stream should be distributed uniformly b. Gas stream should be distributed uniformly c. Both gas as well as liquid streams should be distributed uniformly d. By passing should be completely avoided
|
||||
|
28) Lewis number (Le) is___________________? a. Sc × Pr b. Pr × St c. Sh × Pr d. St × Sh
|
||||
|
29) For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause ____________________ plate requirement? a. No change in theoretical b. Marginal decrease in the number of c. Major decrease in the number of d. None of these
|
||||
|
30) At the boiling point of the liquid at the prevailing pressure, the saturated absolute humidity becomes______________________? a. 1 b. 0 c. ∞ d. None of these
|
||||
|
31) Which of the following is an undesirable property in a tower packing ? a. Large surface per unit volume b. Large free cross-section c. Low weight per unit volume d. Large weight of liquid retained
|
||||
|
32) High pressure at the bottom of a distillation tower handling heat sensitive materials results in _____________________? a. Thermal decomposition of bottoms b. Increased relative volatility c. Erosion of the tower d. Very efficient operation
|
||||
|
33) In the layout plan for a vacuum distillation unit, operating at 60 mm Hg, supported by a barometric condenser, the appropriate place for the location of vacuum drum for collecting the distillate will be_____________________? a. At ground level b. 2 metres above the ground c. 5 metres above ground d. 10 metres above ground
|
||||
|
34) Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a ________________ column? a. Spray b. Packed c. Bubble cap plate d. Wetted wall
|
||||
|
35) Experimental determination of _______________ is done by wetted wall column method? a. Diffusion co-efficient b. Mass transfer co-efficient c. NTU d. None of these
|
||||
|
36) Steady state equimolal counter diffusion is encountered in_____________________? a. Separation of a binary mixture by distillation b. Absorption of NH3 from air by water c. All liquid-liquid diffusion systems d. All liquid-solid diffusion systems
|
||||
|
37) Minimum reflux ratio in a distillation column results in__________________? a. Optimum number of trays b. Minimum reboiler size c. Maximum condenser size d. Minimum number of trays
|
||||
|
38) In case of unsaturated air____________________? a. Dew point < wet bulb temperature b. Wet bulb temperature < dry bulb temperature c. Both A. and B. d. Neither A. not B.
|
||||
|
39) In a binary distillation column, if the feed contains 40 mole % vapour, the q line will have a slope of_________________? a. 1.5 b. -0.6 c. -1.5 d. 0.6
|
||||
|
40) Steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is called the ________________ temperature? a. Dry-bulb b. Wet-bulb c. Dew point d. Adiabatic saturation
|
||||
