(a) How does `H_(2)O` behave as a bleaching agent?
(b) What causes temporary and permanent hardness of water?

Explanation

(a) The bleaching action of `H_(2)O_(2)` is due to oxidation. It oxidation. It oxidises colouring matter to colourless products. For details consult section 9.13
(b) Temporary hardenss in water is caused by bicarbonates of Ca and Mg. Permanent harness results due to the presence of chlorides and sulphate of these metals.