Hardness of Water Multiple Choice Questions and Answers

31. The ion – exchange resins used for softening water are

1. Cross linked polymers with micro porous structure
2. Branched polymers with porous structure
3. Cross linked polymers with non-porous structure
4. Branched polymers with non – porous structure

32. The maximum desirable limits (as per BIS) of total hardness (as CaCO₃) in drinking water is

1. 600 ppm
2. 300 ppm
3. 500 ppm
4. 1000 ppm

33. The method by which ions are pulled out of salt water by direct current, and employing thin and rigid membrane is called

1. Electrodialysis
2. reverse osmosis
3. Zeolite
4. ion exchange

34. The process of allowing water to stand undisturbed in big tanks for settling of the suspended particles due to force of gravity

1. Coagulation
2. conditioning
3. sedimentation
4. screening

35. The process of wet steam formation is called

1. Foaming
2. priming
3. corrosion
4. caustic embrittlement.

36. The purification of brackish water y reverse osmosis is also called as

1. Super – filtration
2. Supra – filtration
3. Hypo – filtration
4. filtration

37. The soft, loose and slimy precipitate formed within the boiler is called

1. Scale
2. sludge
3. embrittlement
4. coagulation

38. Ultraviolet rays are used in the treatment of water for

1. Filtration
2. Sedimentation
3. Screening
4. Sterilization.

39. Uneven deposition of turbines causes

1. Vibrational problems
2. Heat problems
3. Power problems
4. Uncontrolled cooling.

40. When temporary hard water is boiled, one of the substance formed is

1. CaCO₃
2. CaSO₄
3. HCl
4. CO₂