1. If a two phase system is in physical equilibrium; then it means that, the
Correct : D. All (A), (B) and (C)
2. Which of the following remains constant during evaporative cooling process with recirculated water supply?
Correct : C. Wet bulb temperature
3. Weight of 1 m3 of humid air as compared to 1 m3 of dry air, under the same conditions, is
Correct : A. Less
4. Solvent used in extractive distillation
Correct : A. Changes the relative volatility of the original components
5. The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is
Correct : C. Spray chamber
6. CO2 can be absorbed by
Correct : B. Heated charcoal
7. The Knudsen diffusivity is dependent on the
Correct : D. Molecular velocity and pore radius of the catalyst
8. Critical humidity of a solid salt means the humidity
Correct : C. Both (A) and (B)
9. For a binary mixture with low relative volatility, continuous rectification to get pure products will require
Correct : D. High reflux ratio
10. Overall efficiency of the distillation column is
Correct : A. The ratio of number of ideal plates to actual plates
11. The binary diffusivity in gases does not depend upon the
Correct : D. None of these
12. Diffusivity in concentrated solutions differs from that in dilute solutions, because of the changes in
Correct : C. Both (A) and (B)
13. The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are
Correct : C. Both parallel and straight
14. For contacting a highly soluble gas with a liquid
Correct : A. Bubble the gas through liquid
15. Which of the following remains constant during sensible cooling process?
Correct : C. Both (A) and (B)
16. In saturated gas, the
Correct : A. Vapour is in equilibrium with the liquid at the gas temperature
17. In a counter-current extractor, as the axial mixing increases, the extraction efficiency
Correct : B. Decreases
18. At equilibrium the concentration of water in vapour phase (C*) in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is
Correct : C. 0.4
19. In case of absorption with exothermic reaction, for fluids having
Correct : C. Both (A) and (B)
20. Drying operation under vacuum is carried out to
Correct : B. Reduce drying temperature
21. Sticky material can be dried in a __________ dryer.
Correct : A. Tray
22. The drying time between fixed moisture contents within the 'constant rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid).
Correct : B. T
23. The minimum number of theoretical plates is required for achieving a given separation in distillation column with
Correct : B. Total reflux
24. For which of the following unit operations, Lewis number is of significance?
Correct : D. Humidification
25. Heat in BTU necessary to increase the temperature of 1 lb of gas and its accompanying vapour by 1°F is called the
Correct : C. Specific heat
26. With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature).
Correct : A. Increases
27. As the reflux ratio decreases, the
Correct : B. Number of plates increases
28. Only small amount of evaporation of water produces large cooling effects because of its
Correct : A. Large latent heat
29. Ion exchange process is similar to
Correct : B. Adsorption
30. Physical absorption is
Correct : D. Both (B) and (C)
31. Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number.
Correct : A. Schmidt
32. 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
Correct : A. L/G
33. For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of __________ microns (1 mm = 1000 microns).
Correct : B. 10-60
34. Berl saddle made of carbon cannot be used for
Correct : D. Oxidising atmosphere
35. Capacity of a rotary dryer depends on its
Correct : C. Both (A) and (B)
36. The most common packing used in industrial operations is __________ rings.
Correct : A. Raschig
37. Refractory bricks are usually dried in a __________ dryer.
Correct : B. Tunnel
38. Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate.
Correct : B. Decreases
39. The binary diffusivity in gases at atmospheric conditions is about
Correct : B. 10-1 cm2/sec
40. For absorbers, high pressure drop results in
Correct : C. High operating cost
41. __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.