MCQOPTIONS
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MCQOPTIONS
This section includes 122 Mcqs, each offering curated multiple-choice questions to sharpen your Mass Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of h2/ky .Cz is around |
| A. | 0.60 |
| B. | 0.24 |
| C. | 1 |
| D. | 0.72 |
| Answer» D. 0.72 | |
| 2. |
For turbulent mass transfer in pipes, the Sherwood number depends on the Reynoldsnumber as |
| A. | Re0.33 |
| B. | Re0.53 |
| C. | Re0.83 |
| D. | Re |
| Answer» D. Re | |
| 3. |
1 kg of a saturated aqueous solution of a highly soluble component A at 60°C is cooled to 25°C. The solubility limits of A are (0.6 kgA/kg water) at 60°C and (0.2 kgA/kg water) at 25°C. The amount in kg of the crystals formed is: |
| A. | 0.4 |
| B. | 0.25 |
| C. | 0.2 |
| D. | 0.175 |
| Answer» D. 0.175 | |
| 4. |
Psychrometry deals with the properties of gas-vapor mixture. Humidity can be determinedby the measurement of the __________ of a fibre. |
| A. | Electrical resistance |
| B. | Thermal conductivity |
| C. | Strength |
| D. | None of these |
| Answer» B. Thermal conductivity | |
| 5. |
The absorption factor is defined as (where, L = liquid flow rate, G = gas flow rate and, m = slope of the equilibrium line). |
| A. | L/mG |
| B. | G/mL |
| C. | mL/G |
| D. | LG/m |
| Answer» B. G/mL | |
| 6. |
In case of gases, the binary diffusivity is proportional to (where, P = pressure). |
| A. | P |
| B. | 1/P |
| C. | 1/√P |
| D. | √P |
| Answer» C. 1/√P | |
| 7. |
Which of the following is the most suitable for extraction in a system having very lowdensity difference? |
| A. | Mixer-settler extractor |
| B. | Centrifugal extractor |
| C. | Pulsed extractor |
| D. | Packed extraction tower |
| Answer» C. Pulsed extractor | |
| 8. |
Sides of equilateral-triangular co-ordinates (on which ternary liquid system is plotted)represent |
| A. | A pure component |
| B. | A binary mixture |
| C. | A ternary mixture |
| D. | Partially miscible ternary system |
| Answer» C. A ternary mixture | |
| 9. |
Diffusion in concentrated solutions differs from that in dilute solutions, because of the change in the __________ with the concentration of the solution. |
| A. | Degree of ideality |
| B. | Viscosity |
| C. | Both 'a '& 'b' |
| D. | Neither 'a' nor 'b' |
| Answer» D. Neither 'a' nor 'b' | |
| 10. |
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» D. The assumption of constant molal-overflow | |
| 11. |
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» B. Gas viscosity | |
| 12. |
Extraction of penicillin employs a __________ extraction column. |
| A. | Centrifugal |
| B. | Packed |
| C. | Plate |
| D. | None of these |
| Answer» B. Packed | |
| 13. |
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» E. | |
| 14. |
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» B. 1 | |
| 15. |
For __________ drying, the effects of velocity, temperature and humidity of the gas and thethickness of the solid are the same. |
| A. | Unsaturated surface |
| B. | Constant rate |
| C. | Both (A) and (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 16. |
Deaeration (removal of O2) of water is done by |
| A. | Rectification |
| B. | Absorption |
| C. | Ion-exchange |
| D. | Adsorption |
| Answer» D. Adsorption | |
| 17. |
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» D. Evaporation | |
| 18. |
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» B. Separation of sugar from sugar beet by hot water | |
| 19. |
Which of the following remains constant during sensible cooling process? |
| A. | Specific humidity |
| B. | Partial pressure of vapour |
| C. | Both (A) and (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 20. |
Water-ethyl alcohol solution can be concentrated (in respect of alcohol concentration) by __________ distillation. |
| A. | Atmospheric |
| B. | Vacuum |
| C. | High pressure |
| D. | None of these |
| Answer» C. High pressure | |
| 21. |
Which of the following quantities need not be fixed before starting the design of a cocurrent absorber? |
| A. | Heat gain or loss |
| B. | Flow rate of entering liquid |
| C. | Flow rate of gas |
| D. | None of these |
| Answer» C. Flow rate of gas | |
| 22. |
In the absorption of ammonia in water, the main resistance to absorption is by the__________ phase. |
| A. | Liquid |
| B. | Gas |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» C. Both (A) & (B) | |
| 23. |
The relative saturation of a partially saturated mixture of vapour and gas can be increasedby __________ of the mixture. |
| A. | Reducing the total pressure |
| B. | Increasing the total pressure |
| C. | Reducing the temperature |
| D. | Both (B) and (C) |
| Answer» E. | |
| 24. |
If „f’ is defined as above, then which of the following applies to a feed at dew point? |
| A. | f = 1 |
| B. | f < 1 |
| C. | f > 1 |
| D. | 0 < f < 1 |
| Answer» B. f < 1 | |
| 25. |
According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to |
| A. | f |
| B. | f/2 |
| C. | 2f |
| D. | 1/f |
| Answer» C. 2f | |
| 26. |
The McCabe ΔL law states that the |
| A. | Molar heats of vaporisation of components are nearly equal |
| B. | Linear crystal growth rate depends on the degree of super-saturation |
| C. | Linear crystal growth rate does not depend on the crystal size |
| D. | Linear crystal growth rate depends on the crystal size |
| Answer» D. Linear crystal growth rate depends on the crystal size | |
| 27. |
The partial pressure distribution of an ideal gas diffusing through another stagnant idealgas at steady state follows a/an __________ law. |
| A. | Exponential |
| B. | Parabolic |
| C. | Linear |
| D. | Cubic |
| Answer» B. Parabolic | |
| 28. |
At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid__________ that in dry packed tower. |
| A. | Is greater than |
| B. | Is lower than |
| C. | Is same as |
| D. | Cannot be predicted as data are insufficient |
| Answer» B. Is lower than | |
| 29. |
With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature). |
| A. | Increases |
| B. | Remains unchanged |
| C. | Decreases |
| D. | Decreases linearly |
| Answer» B. Remains unchanged | |
| 30. |
If f = moles of vapour present per mole of feed, then the slope of feed line is (McCabeThiele method) |
| A. | (1 - f)/f |
| B. | - (f - 1)/f |
| C. | -1/f |
| D. | -f/(1 - f) |
| Answer» D. -f/(1 - f) | |
| 31. |
Wet bulb and dry bulb temperatures becomes identical at __________ percent saturationcurve. |
| A. | 100 |
| B. | 50 |
| C. | 78 |
| D. | None of these |
| Answer» B. 50 | |
| 32. |
Which of the following is not a unit of mass transfer co-efficient? |
| A. | Moles transferred/ [(time) (area) (mole fraction)] |
| B. | Moles transferred/ [(time) (area) (mass A/mass B)] |
| C. | Moles transferred/ [(time) (area) (pressure)] |
| D. | None of these |
| Answer» E. | |
| 33. |
A coalescer in a mixer-settler liquid-liquid extraction column |
| A. | Comprises of thin bed of substances of extended surface having high porosity |
| B. | Helps in increasing the bubble size entering the settler |
| C. | Helps in increasing the settling rate of the bubbles |
| D. | All 'a', 'b', & 'c' |
| Answer» E. | |
| 34. |
For the same feed, feed quality and separation (in a distillation column), with the increaseof total pressure, the number of ideal plates will |
| A. | Increase |
| B. | Decrease |
| C. | Remain same |
| D. | Data insufficient, can't be predicted |
| Answer» B. Decrease | |
| 35. |
Which of the following employs an accessory known as 'drift eliminator'? |
| A. | Multiple effect evaporator |
| B. | Mechanical draft cooling tower |
| C. | Rotary dryer |
| D. | Rotating disc contactor |
| Answer» C. Rotary dryer | |
| 36. |
The relation, Sc = Pr = 1, is valid, when the mechanism of __________ transfer is same. |
| A. | Heat and mass |
| B. | Mass and momentum |
| C. | Heat and momentum |
| D. | Heat, momentum and mass |
| Answer» B. Mass and momentum | |
| 37. |
The diffusion co-efficient in m2/s. of acetic acid in benzene (liquid in liquid) is |
| A. | 2.09 × 10-4 |
| B. | 2.09 × 10-5 |
| C. | 2.09 × 10-9 |
| D. | 2.09 × 10-12 |
| Answer» B. 2.09 × 10-5 | |
| 38. |
Which of the following gas-liquid contacting devices incurs the least pressure drop for aparticular duty? |
| A. | Grid tray tower |
| B. | Perforated tray tower |
| C. | Wetted wall tower |
| D. | Bubble cap tower |
| Answer» E. | |
| 39. |
With decrease in the throughput (compared with the design capacity) for a bubble capdistillation column, its efficiency |
| A. | Increases |
| B. | Decreases |
| C. | Remain same |
| D. | May increase or decrease; depends on individual design |
| Answer» B. Decreases | |
| 40. |
Mass transfer co-efficient is directly proportional to DAB 0.5, according to __________ theory. |
| A. | Penetration |
| B. | Surface renewal |
| C. | Film |
| D. | None of these |
| Answer» B. Surface renewal | |
| 41. |
Diameter to height ratio for a raschig ring is |
| A. | 1 |
| B. | 0.5 |
| C. | 2 |
| D. | 8 |
| Answer» B. 0.5 | |
| 42. |
Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if |
| A. | Mass transfer is accompanied by reaction |
| B. | Diffusion of A is in stagnant medium B |
| C. | Molecular mean free path is high |
| D. | There is equimolar counter diffusion |
| Answer» E. | |
| 43. |
If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are: |
| A. | Straight |
| B. | Parallel |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 44. |
The expression, ln(F/W) = ∫ xF xW [dx/y* - x)] is |
| A. | Differential distillation equation |
| B. | For NtoG in absorption for dilute mixture |
| C. | Slope of q-line in McCabe-Thiele method |
| D. | For relative volatility |
| Answer» B. For NtoG in absorption for dilute mixture | |
| 45. |
In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter |
| A. | > 4 :1 |
| B. | < 8 : 1 |
| C. | > 8:1 |
| D. | < 6:1 |
| Answer» D. < 6:1 | |
| 46. |
Schmidt number and Lewis number for pure air at atmospheric conditions are respectively |
| A. | < 1 and ≈ 1 |
| B. | 1 and 0 |
| C. | > 1 and ≈ 1 |
| D. | 0 and ≈ 1 |
| Answer» B. 1 and 0 | |
| 47. |
Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off __________ °C. |
| A. | At < 100 |
| B. | At > 210.6 |
| C. | Between 100 and 210 |
| D. | None of these |
| Answer» B. At > 210.6 | |
| 48. |
Condensation of a vapour-gas mixture just begins, when (where, p = partial pressure of the vapour P = vapour pressure of the liquid). |
| A. | p = P |
| B. | p >>P |
| C. | p < P |
| D. | p << P |
| Answer» B. p >>P | |
| 49. |
Molecular sieves are porous |
| A. | Alumina |
| B. | Silica |
| C. | Synthetic zeolites crystals/metal alumino-silicates |
| D. | None of these |
| Answer» D. None of these | |
| 50. |
When the __________ the relative humidity of air decreases, despite an increase in theabsolute humidity. |
| A. | Temperature rises |
| B. | Pressure rises |
| C. | Temperature falls |
| D. | Pressure falls |
| Answer» B. Pressure rises | |