McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 501. |
__________ developed the film theory. |
| A. | Higbie |
| B. | Fick |
| C. | Ergun |
| D. | Levenspiel |
| Answer» A. Higbie | |
| 502. |
Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant. |
| A. | Agitated vessel |
| B. | Sieve tray column |
| C. | Bubble cap column |
| D. | Packed tower |
| Answer» A. Agitated vessel | |
| 503. |
Schmidt number is given by |
| A. | µ/ρDAB |
| B. | Re × Pe |
| C. | Sh × Pe |
| D. | Re/Pe |
| Answer» A. µ/ρDAB | |
| 504. |
Pick out the correct statement. |
| A. | Diffusivity decreases with increase in temperature |
| B. | Diffusivity increases with increase in molecular weight |
| C. | Diffusivity increases with the size of the individual molecule |
| D. | None of these |
| Answer» D. None of these | |
| 505. |
Fenske equation determines the |
| A. | Maximum number of ideal plates |
| B. | Height of the distillation column |
| C. | Minimum number of theoretical plates |
| D. | Optimum reflux ratio |
| Answer» C. Minimum number of theoretical plates | |
| 506. |
If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively |
| A. | [xD/(RD + 1)], [RD/(RD + 1)] |
| B. | [RD/(RD + 1)], [xD/(xD + 1)] |
| C. | [xD/(RD + 1)], [(RD + 1)/RD] |
| D. | None of these |
| Answer» B. [RD/(RD + 1)], [xD/(xD + 1)] | |
| 507. |
Which of the following equipments is not used for gas dispersion? |
| A. | Agitated vessels |
| B. | Bubble cap tray towers |
| C. | Perforated sieve tray towers |
| D. | Spray towers |
| Answer» D. Spray towers | |
| 508. |
__________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids. |
| A. | Wetted wall |
| B. | Packed |
| C. | Plate |
| D. | Spray |
| Answer» C. Plate | |
| 509. |
When adsorption hysteresis is observed, the desorption equilibrium pressure is __________ that obtained by adsorption. |
| A. | Always lower than |
| B. | Always higher than |
| C. | Same as |
| D. | Dependent on the system; can be either lower or higher than |
| Answer» A. Always lower than | |
| 510. |
On addition of solute in the solvent, the __________ of the solution decreases. |
| A. | Boiling point |
| B. | Freezing point |
| C. | Vapour pressure |
| D. | Both (B) and (C) |
| Answer» D. Both (B) and (C) | |
| 511. |
Extraction of penicillin employs a __________ extraction column. |
| A. | Centrifugal |
| B. | Packed |
| C. | Plate |
| D. | None of these |
| Answer» A. Centrifugal | |
| 512. |
Which of these columns incurs the lowest pressure drop? |
| A. | Packed column (with stacked packing) |
| B. | Packed column (with dumped packing) |
| C. | Bubble plate column |
| D. | Pulse column |
| Answer» A. Packed column (with stacked packing) | |
| 513. |
'Absorption with chemical reaction' is involved in the removal of |
| A. | Carbon dioxide from gaseous stream using alkaline solution |
| B. | Benzol from coke oven gas using solar oil/wash oil |
| C. | Ammonia from coke oven gas using refrigerated water |
| D. | Tar from coke oven gas in primary gas coolers using chilled water |
| Answer» A. Carbon dioxide from gaseous stream using alkaline solution | |
| 514. |
Which of the following mixtures does not form an azeotrope at atmospheric pressure? |
| A. | Water-alcohol |
| B. | Methyl alcohol-acetone |
| C. | Butyl acetate-water |
| D. | None of these |
| Answer» D. None of these | |
| 515. |
In batch distillation with constant reflux, overhead product composition __________ with time. |
| A. | Increases |
| B. | Decreases |
| C. | Does not vary |
| D. | May increase on decrease, depends on the system |
| Answer» B. Decreases | |
| 516. |
McCabe-Thiele method of binary distillation does not assume that the |
| A. | Sensible heat changes are negligible compared with latent heat changes |
| B. | Molar latent heats of all components are equal |
| C. | Heat of mixing is negligible |
| D. | None of these |
| Answer» D. None of these | |
| 517. |
Which of the following same diameter columns gives lowest pressure drop per unit height? |
| A. | Bubble-cap column |
| B. | Sieve-plate column |
| C. | Packed column (stacked) |
| D. | Randomly packed column |
| Answer» C. Packed column (stacked) | |
| 518. |
Absorption factor method is used to calculate the number of ideal stages, when |
| A. | Operating line lies above the equilibrium line |
| B. | Operating line lies below the equilibrium line |
| C. | Both operating and equilibrium lines are parallel |
| D. | Pressure drop in the column is very high |
| Answer» C. Both operating and equilibrium lines are parallel | |
| 519. |
Entrainer used in Azeotropic distillation should |
| A. | Form a low boiling azeotrope with one of the constituents of the mixture |
| B. | Form a new azeotrope of low relative volatility with one of the constituents of the mixture |
| C. | Have high latent heat of vaporisation |
| D. | Have high viscosity to provide high tray efficiency |
| Answer» A. Form a low boiling azeotrope with one of the constituents of the mixture | |
| 520. |
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? |
| A. | Zero |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» A. Zero | |
| 521. |
For the same process conditions, the reflux ratio of an unlagged distillation column |
| A. | Decreases in winter |
| B. | Increases in winter |
| C. | Increases in summer |
| D. | None of these |
| Answer» B. Increases in winter | |
| 522. |
Minimum possible diameter of a packed column is decided mainly by the |
| A. | Flooding |
| B. | Gas viscosity |
| C. | Liquid density |
| D. | Liquid hold up |
| Answer» A. Flooding | |
| 523. |
Ponchon-Savarit method analyses the fractional equipment based on |
| A. | Enthalpy balance only |
| B. | Material balance only |
| C. | Both enthalpy and material balances |
| D. | The assumption of constant molal-overflow |
| Answer» C. Both enthalpy and material balances | |
| 524. |
Dryer widely used in a textile industry is __________ dryer. |
| A. | Festoon |
| B. | Cylinder |
| C. | Conveyor |
| D. | Tunnel |
| Answer» C. Conveyor | |
| 525. |
Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty? |
| A. | Sieve plate column |
| B. | Bubble cap column |
| C. | Randomly packed column |
| D. | Wetted wall column |
| Answer» D. Wetted wall column | |
| 526. |
In a binary system, separation is very efficient, when the relative volatility is |
| A. | 1 |
| B. | > 1 |
| C. | < 1 |
| D. | 0.5 |
| Answer» B. > 1 | |
| 527. |
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. |
| A. | T1-Dew point temp; T2-Dry bulb temp; T3-Wet bulb temp |
| B. | T1-Dew point temp; T2-Wet bulb temp; T3-Dry bulb temp |
| C. | T1-Wet bulb temp; T2-Dry bulb temp; T3-Dew point temp |
| D. | T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp |
| Answer» D. T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp | |
| 528. |
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» D. Both (B) and (C) | |
| 529. |
Which of the following adsorbent is used in the refining of sugar? |
| A. | Bone charcoal |
| B. | Wood charcoal |
| C. | Silica gel |
| D. | Activated clay |
| Answer» A. Bone charcoal | |
| 530. |
With increase in pressure, the relative volatility for a binary system |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | Either (A) or (B), depends on the system |
| Answer» B. Decreases | |
| 531. |
When the liquid over a plate is of uniform concentration, then |
| A. | Murphree efficiency > point efficiency |
| B. | Murphree efficiency < point efficiency |
| C. | Murphree efficiency = point efficiency |
| D. | Murphree efficiency ≠ point efficiency |
| Answer» C. Murphree efficiency = point efficiency | |
| 532. |
Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when |
| A. | Extracting solvent is cheaply & abundantly available |
| B. | One of the liquid components is heat sensitive |
| C. | Viscosity of liquid components is very high |
| D. | One of the liquid components has very high affinity towards the solvent |
| Answer» D. One of the liquid components has very high affinity towards the solvent | |
| 533. |
A good solvent used for absorption should not have very high |
| A. | Viscosity |
| B. | Vapor pressure |
| C. | Freezing point |
| D. | All (A), (B) & (C) |
| Answer» D. All (A), (B) & (C) | |
| 534. |
An example of elution is |
| A. | Separation of uranium oxide from its ore by H2SO4 in a Pachuca tank |
| B. | Separation of sugar from sugar beet by hot water |
| C. | Dissolution of tannin out of tree barks by water |
| D. | Recovery of vegetable oils from seeds |
| Answer» A. Separation of uranium oxide from its ore by H2SO4 in a Pachuca tank | |
| 535. |
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» C. Hot water entering the tower and the cooled water leaving the tower | |
| 536. |
If the amount of the steam used in steam distillation is increased, the temperature of distillation |
| A. | Increases |
| B. | Decreases |
| C. | Remains unchanged |
| D. | Depends on relative volatility |
| Answer» B. Decreases | |
| 537. |
Rate of leaching increases with increasing |
| A. | Temperature |
| B. | Viscosity of solvent |
| C. | Pressure |
| D. | Size of the solid |
| Answer» A. Temperature | |
| 538. |
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» A. Increases | |
| 539. |
Heat load in a cooling tower |
| A. | Means the amount of heat thrown away (KCal/hr.) by the cooling tower |
| B. | Is equal to the number of kg, of water circulated times the cooling range |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» C. Both (A) & (B) | |
| 540. |
Separation of two or more components of a liquid solution cannot be achieved by |
| A. | Fractional crystallisation |
| B. | Liquid extraction |
| C. | Absorption |
| D. | Evaporation |
| Answer» C. Absorption | |
| 541. |
For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. |
| A. | Unsaturated surface |
| B. | Constant rate |
| C. | Both (A) and (B) |
| D. | Neither (A) nor (B) |
| Answer» C. Both (A) and (B) | |
| 542. |
In continuous distillation, the internal reflux ratio (Ri) and the external reflux ratio (Re) are related as |
| A. | Ri = Re/(1 - Re) |
| B. | Ri = (1 - Re)/Re |
| C. | Ri = Re |
| D. | Ri = Re/(1 + Re) |
| Answer» D. Ri = Re/(1 + Re) | |
| 543. |
Deaeration (removal of O2) of water is done by |
| A. | Rectification |
| B. | Absorption |
| C. | Ion-exchange |
| D. | Adsorption |
| Answer» C. Ion-exchange | |
| 544. |
For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because |
| A. | Water has a high latent heat of evaporation |
| B. | Lewis number is close to unity |
| C. | They are always equal under all circumstances |
| D. | Solubility of the components of air in water is very small |
| Answer» A. Water has a high latent heat of evaporation | |
| 545. |
Dew point of a gas-vapour mixture |
| A. | Increases with temperature rise |
| B. | Decreases with temperature rise |
| C. | Decreases with decrease in pressure |
| D. | Increases with increase in pressure |
| Answer» C. Decreases with decrease in pressure | |
| 546. |
If moisture content of solid on dry basis is X, then the same on wet basis is |
| A. | X/(X + 1) |
| B. | X/(1 - X) |
| C. | (1 + X)/X |
| D. | (1 - X)/X |
| Answer» A. X/(X + 1) | |
| 547. |
__________ 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» B. Wet bulb | |
| 548. |
The-relative volatility for separation of a non-ideal binary mixture by distillation should be |
| A. | 0 |
| B. | 1 |
| C. | > 1 |
| D. | < 1 |
| Answer» C. > 1 | |
| 549. |
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» C. Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition | |
| 550. |
Which of the following unit operations makes use of Thiele-Geddes equation? |
| A. | Liquid-liquid extraction |
| B. | Solid-liquid extraction |
| C. | Multi-component absorption with chemical reaction |
| D. | Multi-component distillation |
| Answer» D. Multi-component distillation | |
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