MCQOPTIONS
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MCQOPTIONS
This section includes 854 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
L/mG is the expression for |
| A. | absorption factor |
| B. | Brinkman number |
| C. | slope of operating line in absorber |
| D. | slope of operating line in stripper. |
| Answer» B. Brinkman number | |
| 452. |
In an absorber, HETP does not vary with the |
| A. | flow rate of liquid |
| B. | flow rate of gas |
| C. | type and size of packing |
| D. | none of these |
| Answer» E. | |
| 453. |
Drift in a cooling tower is |
| A. | the water entrained by the circulating air. |
| B. | dependent on the water lost by evaporation. |
| C. | desirable. |
| D. | all (a), (b) & (c). |
| Answer» B. dependent on the water lost by evaporation. | |
| 454. |
(NRe . NSc) is termed in mass transfer operation as the __________ number. |
| A. | Stanton |
| B. | Sherwood |
| C. | Peclet |
| D. | none of these |
| Answer» D. none of these | |
| 455. |
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 |
| Answer» B. 1200 | |
| 456. |
Flash distillation is |
| A. | same as differential distillation. |
| B. | used for multicomponent systems like crude refining. |
| C. | same as simple distillation. |
| D. | most useful for handling binary systems. |
| Answer» C. same as simple distillation. | |
| 457. |
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' | |
| 458. |
Inside the distillation columns, the |
| A. | highest temperatures is near the feed plate. |
| B. | driving force for the liquid flow is its weight. |
| C. | vapors are not always at their dew points. |
| D. | all (a), (b) and (c) |
| Answer» C. vapors are not always at their dew points. | |
| 459. |
In case of a desorber (stripper), the |
| A. | operating line always lies above the equilibrium curve. |
| B. | operating line always lies below the equilibrium curve. |
| C. | temperature remains unaffected. |
| D. | temperature always increases. |
| Answer» C. temperature remains unaffected. | |
| 460. |
Pick out the wrong statement. Generally for physical adsorption, a gas of |
| A. | higher molecular weight is adsorbed in preference to a gas of low molecular weight. |
| B. | high critical temperature is adsorbed in preference to a gas of low critical temperature. |
| C. | low volatility is adsorbed in preference to a gas of high volatility. |
| D. | none of these. |
| Answer» E. | |
| 461. |
According to Chilton-Colburn analogy for mass transfer, NSt.NSc2/3 is equal to |
| A. | f |
| B. | f/2 |
| C. | 2f |
| D. | 1/f |
| Answer» C. 2f | |
| 462. |
For stripping of a gas in a counter current stripper, the operating line |
| A. | lies above the equilibrium curve. |
| B. | lies below the equilibrium curve. |
| C. | can lie above or below the equilibrium curve. |
| D. | is always parallel to the equilibrium curve. |
| Answer» D. is always parallel to the equilibrium curve. | |
| 463. |
Dimension of mass diffusivity is the same as that of |
| A. | kinematic viscosity |
| B. | dynamic viscosity |
| C. | surface tension |
| D. | pressure |
| Answer» B. dynamic viscosity | |
| 464. |
Leaching rate is independent of the |
| A. | agitation |
| B. | temperature |
| C. | particle size |
| D. | none of these |
| Answer» E. | |
| 465. |
Diameter to height ratio for a rashig ring is |
| A. | 1 |
| B. | 0.5 |
| C. | 2 |
| D. | 8 |
| Answer» B. 0.5 | |
| 466. |
Lewis number (Le) is |
| A. | Sc x Pr |
| B. | Pr x St |
| C. | Sh x Pr |
| D. | St x Sh |
| Answer» B. Pr x St | |
| 467. |
Which of the following increases during evaporative cooling process with recirculated water supply ? |
| A. | Wet bulb temperature |
| B. | Relative humidity |
| C. | Partial pressure of vapour |
| D. | Both (b) and (c) |
| Answer» E. | |
| 468. |
With increase in temperature, the mutual solubility of two liquids |
| A. | increases |
| B. | decreases |
| C. | remains unchanged |
| D. | decreases exponentially |
| Answer» B. decreases | |
| 469. |
Azeotropism for ethyl alcohol-water system disappears by |
| A. | increasing temperature |
| B. | decreasing pressure |
| C. | increasing pressure |
| D. | no means |
| Answer» C. increasing pressure | |
| 470. |
__________ is concerned with the adsorption equilibria. |
| A. | Fick's law |
| B. | Gibb's equation |
| C. | Freundlich equation |
| D. | none of these |
| Answer» D. none of these | |
| 471. |
Leaching of sugar from sugar beets is done by |
| A. | hot water |
| B. | hexane |
| C. | dilute H2SO4 |
| D. | lime water |
| Answer» B. hexane | |
| 472. |
Mass transfer co-efficient is defined as |
| A. | Flux = Co-efficient/concentration difference. |
| B. | Co-efficient = Flux/concentration difference. |
| C. | Flux=concentration difference/co-effi-cient. |
| D. | none of these. |
| Answer» C. Flux=concentration difference/co-effi-cient. | |
| 473. |
In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapour, because |
| A. | temperature is less. |
| B. | total pressure is less. |
| C. | mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition. |
| D. | saturated steam is used for steam distillation. |
| Answer» D. saturated steam is used for steam distillation. | |
| 474. |
Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in terms of __________ humidity. |
| A. | molal |
| B. | relative |
| C. | percentage |
| D. | none of these |
| Answer» B. relative | |
| 475. |
Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. |
| A. | wetted wall |
| B. | bubble cap |
| C. | perforated tray |
| D. | packed |
| Answer» B. bubble cap | |
| 476. |
Which of the following is the most commonly used leaching solvent in vegetable oil industry ? |
| A. | Phenol |
| B. | Hexane |
| C. | Furfurol |
| D. | Liquid SO2 |
| Answer» C. Furfurol | |
| 477. |
Refractory bricks are usually dried in a __________ dryer. |
| A. | tray |
| B. | tunnel |
| C. | conveyor |
| D. | festoon |
| Answer» C. conveyor | |
| 478. |
Lewis number, which is important in problems involving simultaneous heat and mass transfer, is the ratio of |
| A. | mass diffusivity to momentum diffusivity. |
| B. | thermal diffusivity to mass diffusivity. |
| C. | momentum diffusivity to thermal diffusivity. |
| D. | none of these. |
| Answer» C. momentum diffusivity to thermal diffusivity. | |
| 479. |
For a ternery 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. | ternery mixture is represented by the sides |
| D. | pure component is represented by the apex. |
| Answer» E. | |
| 480. |
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 | |
| 481. |
Selectivity of the solvent used in solvent extraction should be |
| A. | 1 |
| B. | > 1 |
| C. | < 1 |
| D. | 0 |
| Answer» C. < 1 | |
| 482. |
__________ column is used in gas absorption process. |
| A. | Wetted wall |
| B. | Seive/perforated tray |
| C. | Bubble cap |
| D. | Packed |
| Answer» E. | |
| 483. |
If G = insoluble gas in gas stream and L = non-volatile solvent in liquid stream, then the slope of the operating line for the absorber is |
| A. | L/G |
| B. | G/L |
| C. | always < 1 |
| D. | none of these |
| Answer» B. G/L | |
| 484. |
(NSh/NRe.NSc) is termed in mass transfer operation as the |
| A. | Stanton number |
| B. | Peclet number |
| C. | thermal diffusivity |
| D. | momentum diffusivity |
| Answer» B. Peclet number | |
| 485. |
Plate efficiency |
| A. | is a function of the mass transfer between liquid and vapour. |
| B. | increases due to foaming. |
| C. | increases due to liquid entrainment. |
| D. | increases due to weeping and dumping of liquid. |
| Answer» B. increases due to foaming. | |
| 486. |
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 |
| Answer» D. 0.6 | |
| 487. |
Operating velocity in a packed tower is usually __________ the flooding velocity. |
| A. | half |
| B. | twice |
| C. | equal to |
| D. | more than |
| Answer» B. twice | |
| 488. |
Swenson-Walker crystalliser is a __________ unit |
| A. | continuous |
| B. | batch |
| C. | semi-batch |
| D. | cooling (adiabatic)-cum-evaporation |
| Answer» B. batch | |
| 489. |
Schmidt number is given by |
| A. | |
| B. | Re.Pe |
| C. | Sh x Pe |
| Answer» B. Re.Pe | |
| 490. |
Which of the following solutions will follow Raoult's law most closely ? |
| A. | A solution of benzene, toluene and oxylene. |
| B. | 35% solution of camphor in water. |
| C. | 35% solution of NH3 in water. |
| D. | A solution of polar organic compounds (not of homologs of a series). |
| Answer» B. 35% solution of camphor in water. | |
| 491. |
__________ equation applies to diffusivities in liquids. |
| A. | Gilliland |
| B. | Hirschfelder |
| C. | Wilke and Chang |
| D. | none of these |
| Answer» B. Hirschfelder | |
| 492. |
Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and 't' is time) |
| A. | (De.t)1/2 |
| B. | (De/t)1/2 |
| C. | (4De/πt)1/2 |
| D. | (4De/t) |
| Answer» D. (4De/t) | |
| 493. |
Rate of leaching increases with increasing |
| A. | temperature |
| B. | viscosity of solvent |
| C. | pressure |
| D. | size of the solid |
| Answer» B. viscosity of solvent | |
| 494. |
Flights in a rotary dryer are provided to |
| A. | lift and shower the solids thus exposing it thoroughly to the drying action of the gas. |
| B. | reduce the residence time of solid. |
| C. | increase the residence time of the solid. |
| D. | none of these. |
| Answer» B. reduce the residence time of solid. | |
| 495. |
In most of the vacuum crystalliser, vacuum is generally produced by means of a |
| A. | suction pump |
| B. | compressed air jet |
| C. | steam jet ejector with a barometric condenser |
| D. | none of these |
| Answer» D. none of these | |
| 496. |
Coffee is prepared from coffee beans by leaching with |
| A. | cold water |
| B. | hot water |
| C. | dilute hot caustic solution |
| D. | naphtha |
| Answer» C. dilute hot caustic solution | |
| 497. |
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. |
| Answer» D. minimum number of trays. | |
| 498. |
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 | |
| 499. |
Dew point of an air-water vapor mixture |
| A. | decreases with decrease in pressure. |
| B. | at constant humidity & total pressure is fixed. |
| C. | corresponding to any point on the humidity chart is obtained by projecting a line through this point parallel to the temperature axis and to the saturation curve. |
| D. | all 'a', 'b' & 'c'. |
| Answer» E. | |
| 500. |
__________ developed the film theory. |
| A. | Higbie |
| B. | Fick |
| C. | Ergun |
| D. | Levenspeil |
| Answer» B. Fick | |