MCQOPTIONS
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MCQOPTIONS
This section includes 591 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
_The temperature of water cooled in cooling tower is always __________ temperature of entering air.$? |
| A. | More than the wet bulb |
| B. | Less than the wet bulb |
| C. | Equal to the wet bulb |
| D. | Equal to the dry bulb |
| Answer» B. Less than the wet bulb | |
| 402. |
_Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve.$? |
| A. | 100 |
| B. | 50 |
| C. | 78 |
| D. | None of these |
| Answer» B. 50 | |
| 403. |
To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)$? |
| A. | Increase both 'G' and 'S' |
| B. | Decrease both 'G' and 'S' |
| C. | Increase 'S' and decrease 'G' |
| D. | Increase 'G' and decrease 'S' |
| Answer» D. Increase 'G' and decrease 'S' | |
| 404. |
Radioactive nuclear waste is treated in$? |
| A. | Mixer-settler extractor |
| B. | Rotating-disc contactor |
| C. | Pulsed column extractor |
| D. | Bollman extractor |
| Answer» D. Bollman extractor | |
| 405. |
Large quantity of silica gel is normally dried in a __________ dryer.$? |
| A. | Freeze |
| B. | Through circulation |
| C. | Rotary vacuum |
| D. | Tray |
| Answer» C. Rotary vacuum | |
| 406. |
At minimum reflux ratio for a given separation$? |
| A. | Number of plates is zero |
| B. | Number of plates is infinity |
| C. | Minimum number of the theoretical plates is required |
| D. | Separation is most efficient |
| Answer» C. Minimum number of the theoretical plates is required | |
| 407. |
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$? |
| A. | Liquid phase resistance-controlled |
| B. | Gas phase resistance controlled |
| C. | Impossible |
| D. | Driven by a non-linear driving force |
| Answer» C. Impossible | |
| 408. |
Can a cooling tower cool water below the wet bulb temperature of inlet air?$? |
| A. | Yes |
| B. | No |
| C. | Yes ; but height of cooling tower will be prohibitively high |
| D. | Yes ; but the air flow rate should be excessively high |
| Answer» C. Yes ; but height of cooling tower will be prohibitively high | |
| 409. |
Rose oil is extracted from rose leaves using __________ distillation.$? |
| A. | High pressure |
| B. | Low pressure |
| C. | Extractive |
| D. | Steam |
| Answer» E. | |
| 410. |
In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the$? |
| A. | Range is 15°F |
| B. | Approach is 10°F |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 411. |
__________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gas-vapor mixture.$? |
| A. | Dry bulb |
| B. | Wet bulb |
| C. | Dew point |
| D. | None of these |
| Answer» C. Dew point | |
| 412. |
Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are$? |
| A. | 1 |
| B. | 8 |
| C. | 9 |
| D. | 10 |
| Answer» D. 10 | |
| 413. |
Which of the following increases during evaporative cooling process with recirculated water supply?$? |
| A. | Wet bulb temperature |
| B. | Relative humidity |
| C. | Partial pressure of vapour |
| D. | Both B and C |
| Answer» E. | |
| 414. |
When an unsaturated air-water mixture is heated at constant pressure, then$? |
| A. | The partial pressure of water vapour increases |
| B. | The specific humidity decreases |
| C. | The relative humidity increases |
| D. | The relative humidity decreases |
| Answer» E. | |
| 415. |
For an absorber, both equilibrium and operating line will be straight for$? |
| A. | Concentrated solution and non-isothermal operation |
| B. | Dilute solution and non-isothermal operation |
| C. | Dilute solution and isothermal operation |
| D. | Concentrated solution and isothermal operation |
| Answer» D. Concentrated solution and isothermal operation | |
| 416. |
Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower.$? |
| A. | Wetted wall |
| B. | Bubble cap |
| C. | Perforated tray |
| D. | Packed |
| Answer» B. Bubble cap | |
| 417. |
In which of the following unit operations, the selectivity is an important parameter?$? |
| A. | Distillation |
| B. | Solvent extraction |
| C. | Absorption |
| D. | None of these |
| Answer» C. Absorption | |
| 418. |
Paper industry employs __________ driers.$? |
| A. | Cylinder |
| B. | Rotary |
| C. | Spray |
| D. | Fluidised bed |
| Answer» B. Rotary | |
| 419. |
The velocity, concentration and temperature boundary, for the boundary layer development on a flat plate during connective mass transfer will be same, if$? |
| A. | NSc = 1 |
| B. | NSc = NPr = NLe |
| C. | NPr = NLe |
| D. | NSc = NLe |
| Answer» C. NPr = NLe | |
| 420. |
Molecular distillation is$? |
| A. | High temperature distillation |
| B. | For heat-sensitive materials |
| C. | Very low pressure distillation |
| D. | Both B and C |
| Answer» E. | |
| 421. |
With increase in gas rate, the number of transfer units, NtoG, for a fixed degree of absorption by a fixed amount of solvent$? |
| A. | Increases |
| B. | Decreases |
| C. | Decreases linearly |
| D. | Remains unaffected |
| Answer» B. Decreases | |
| 422. |
If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that$? |
| A. | The system comprises of partially mis-cible liquids |
| B. | The system comprises of miscible liquids |
| C. | The system comprises of an azeotrope |
| D. | On heating, a vapor phase will appear ; while on cooling, a solid phase will appear |
| Answer» E. | |
| 423. |
Minimum reflux ratio in a distillation column results in$? |
| A. | Optimum number of trays |
| B. | Minimum reboiler size |
| C. | Maximum condenser size |
| D. | Minimum number of trays |
| Answer» D. Minimum number of trays | |
| 424. |
Liquid diffusivity is of the order of __________ cm² /second.$? |
| A. | 0.01 |
| B. | 0.1 |
| C. | 10-5 to 10-6 |
| D. | > 1 |
| Answer» D. > 1 | |
| 425. |
The binary diffusivity in gases and liquids vary respectively as$? |
| A. | T3/2 and T |
| B. | T and T3/2 |
| C. | ‚à öT and T3/2 |
| D. | T3/2 and ‚à öT |
| Answer» B. T and T3/2 | |
| 426. |
In extractive distillation, solvent is$? |
| A. | Added to alter the relative volatility of the mixture |
| B. | Of high volatility |
| C. | Present in overhead stream |
| D. | Of high viscosity to give high tray efficiency |
| Answer» B. Of high volatility | |
| 427. |
CO‚ÇÇ can be absorbed by$? |
| A. | Hot cupric oxide |
| B. | Heated charcoal |
| C. | Cold Ca(OH)‚ÇÇ |
| D. | Alumina |
| Answer» C. Cold Ca(OH)‚Äö√á√á | |
| 428. |
Which of the following provides maximum contact surface for a liquid-vapour system?$? |
| A. | Packed tower |
| B. | Bubble-cap plate column |
| C. | Seive-plate column |
| D. | Wetted wall column |
| Answer» B. Bubble-cap plate column | |
| 429. |
Blowdown in a cooling tower$? |
| A. | Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities |
| B. | Increases the scale forming tendencies of water |
| C. | Is undesirable |
| D. | All of the above |
| Answer» B. Increases the scale forming tendencies of water | |
| 430. |
NSc/NPr is called the$? |
| A. | Psychrometric ratio |
| B. | Lewis number |
| C. | Sherwood number |
| D. | Stantan number |
| Answer» C. Sherwood number | |
| 431. |
__________ diffusion is used for separating the isotopes of methane.$? |
| A. | Thermal |
| B. | Pressure |
| C. | Concentration |
| D. | Force |
| Answer» B. Pressure | |
| 432. |
In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the __________ number.$? |
| A. | Lewis |
| B. | Grashoff |
| C. | Sherwood |
| D. | None of these |
| Answer» B. Grashoff | |
| 433. |
In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalant to a theoretical plate HTUOG = overall gas phase height of a transfer unit)$? |
| A. | Straight |
| B. | Parallel |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 434. |
In extraction, as the temperature increases, the area of hetrogeneity (area covered by binodal curve)$? |
| A. | Decreases |
| B. | Increases |
| C. | Remains unchanged |
| D. | None of these |
| Answer» B. Increases | |
| 435. |
Dry bulb temperature of unsaturated air is more than its __________ temperature.$? |
| A. | Dew point |
| B. | Wet bulb |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 436. |
The equilibrium liquid composition compared to the vapor composition in case of azeotropic mixture is$? |
| A. | More |
| B. | Less |
| C. | Same |
| D. | Either more or less; depends on the system |
| Answer» D. Either more or less; depends on the system | |
| 437. |
Which of the following is directly concerned with psychrometry?$? |
| A. | Lewis reltionship |
| B. | Galileo number |
| C. | Weber number |
| D. | Dean number |
| Answer» B. Galileo number | |
| 438. |
In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer.$? |
| A. | The entire amount of C is transferred to solvent B |
| B. | Less than 2 kg but more than 1 kg of C is transferred to solvent B |
| C. | Less than 1 kg of C is transferred to B |
| D. | No amount of C is tranferred to B |
| Answer» B. Less than 2 kg but more than 1 kg of C is transferred to solvent B | |
| 439. |
With increase in temperature, the leaching rate increases because of the$? |
| A. | Increased diffusivity |
| B. | Decreased viscosity of liquid |
| C. | Both A and B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 440. |
Channelling in a packed tower results from the$? |
| A. | High pressure drop |
| B. | Maldistribution of liquid |
| C. | Non-uniformity of packing |
| D. | Both B and C |
| Answer» E. | |
| 441. |
Psychrometry deals with the properties of gas-vapor mixture. Humidity can be determined by the measurement of the __________ of a fibre.$? |
| A. | Electrical resistance |
| B. | Thermal conductivity |
| C. | Strength |
| D. | None of these |
| Answer» B. Thermal conductivity | |
| 442. |
The relation, Sc = Pr = 1, is valid, when the mechanism of __________ ansfer is same.$? |
| A. | Heat and mass |
| B. | Mass and momentum |
| C. | Heat and momentum |
| D. | Heat, momentum and mass |
| Answer» B. Mass and momentum | |
| 443. |
In a gas-liquid absorption coloumn, for obtaining the maximum absorption efficiency$? |
| A. | Liquid stream should be distributed uniformly |
| B. | Gas stream should be distributed uniformly |
| C. | Both gas as well as liquid streams should be distributed uniformly |
| D. | By passing should be completely avoided |
| Answer» D. By passing should be completely avoided | |
| 444. |
The diffusion co-efficient in m² /s. of acetic acid in benzene (liquid in liquid) is$? |
| A. | 2.09 x 10-4 |
| B. | 2.09 x 10-5 |
| C. | 2.09 x 10-9 |
| D. | 2.09 x 10-12 |
| Answer» B. 2.09 x 10-5 | |
| 445. |
With increase in temperature, the solubility of gases in liquids, at fixed pressure$? |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | Either A or B, depends on the system |
| Answer» C. Remains same | |
| 446. |
Most important factor to be considered in the selection of packings for absorbers is the __________ of packing.$? |
| A. | Size |
| B. | Durability |
| C. | Porosity |
| D. | Cost |
| Answer» D. Cost | |
| 447. |
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$? |
| A. | The product composition but not the fraction vaporised |
| B. | The product composition as well as the fraction vaporised |
| C. | The fraction vaporised but not the product composition |
| D. | Neither the product composition nor the fraction vaporised |
| Answer» D. Neither the product composition nor the fraction vaporised | |
| 448. |
The solvent used in liquid extraction should not have high latent heat of vaporisation, because$? |
| 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 prohibitatively high |
| D. | It will decompose while recovering by distillation |
| Answer» D. It will decompose while recovering by distillation | |
| 449. |
Flash distillation is$? |
| A. | Same as differential distillation |
| B. | Used for multicomponent systems like crude refining |
| C. | Same as simple distillation |
| D. | Most useful for handling binary systems |
| Answer» C. Same as simple distillation | |
| 450. |
An ideal tower packing should not$? |
| A. | Have low weight per unit volume |
| B. | Have large surface area per unit volume |
| C. | Have large free cross-section |
| D. | Hold up large amount of liquid in the packing |
| Answer» E. | |