Hardness of Water Multiple Choice Questions and Answers

11. Estimation of hardness of water by EDTA method is used to determine

1. Alkaline hardness
2. temporary hardness only
3. Permanent hardness only
4. all the above

12. Hard water can be softened by passing it through

1. Lime stone
2. sodium hexa meta phosphate
3. Ion – exchange resin
4. sodium silicate

13. Hard water is unfit for use in boilers for generating steam because

1. Its boiling point is high
2. Hard water does not produce lather inside boiler
3. Water decomposes into O2 and H2
4. It produces scales inside the boiler

14. Hardness in water is caused due to the presence of

1. Undissolved salts of Ca²⁺ and Mg²⁺
2. Dissolved sulfates of Potassium
3. Dissolved salts of Ca²⁺ and Mg²⁺
4. Undissolved CaCO₃

15. Hardness of water does not

1. Have any bad effect in boiler
2. make cooking of food difficult
3. Make it unfit for drinking
4. cause difficulty in washing clothes with soaps.

16. Hardness of water is expressed in equivalents of

1. CaCO₃
2. MgCO₃
3. Ca(HCO₃)₂
4. Mg(HCO³)²

17. Hardness of water is measured in

1. Degree Clarke
2. ppm
3. degree French
4. mg /L

18. Liquid chlorine is a most effective

1. Disinfectant
2. coagulant
3. floculant
4. sterilizing agent

19. One of the following chemical acts as both coagulant and softening agent

1. Lime
2. soda
3. soda
4. sodium aluminate

20. One of the following is an example for cation exchanging resin

1. Copolymer of phenol formaldehyde – amine formaldehyde
2. Copolymer of styrene – divinyl benzene
3. Copolymer of phenol formaldehyde and styrene
4. Copolymer of amine formaldehyde and divinely benzene