What do you understand by:

(a) Soft water

(b) Hard water

(c) Temporary Hard water

(d) Permanent hard water.

(a) Soft water — Water is said to be soft water if it readily forms lather with soap.

(b) Hard water — Water is said to be hard if it does not readily form lather with soap.

(c) Temporary Hard water — Water that contains only hydrogen carbonates of Calcium and Magnesium is called temporary hard water.

(d) Permanent hard water — Water that contains sulphates and chlorides of Magnesium and Calcium is called Permanent hard water.