Bleaching action of chlorine is permanent - Justify this statement and also give the uses of chlorine.

Explanation

Chlorine is a strong oxidising and bleaching agent because of the nascent oxygen.
`H_(2)O+Cl_(2) to HCl+underset("Hypo chlorous acid")(HOCl)`
`HOCl to HCl +(O)`
Colouring matter + Nascent oxygen `to` Colourless oxidation product
Therefore, bleaching of chlorine is permanent. It oxidises ferrous salts to ferric, sulphites to sulphates and hydrogen sulphide to sulphur.
(i) `underset(("Ferrous"))(2FeSO_(4))+H_(2)SO_(4)+HOCl to underset(("Ferric"))(Fe_(2)(SO_(4))_(3)+HCl +H_(2)O`
(ii) `underset(("Sulphite"))(Na_(2)SO_(3))+HOCl to underset(("Sulphate"))(Na_(2)SO_(4))+HCl`
(iii) `underset(("Sulphide"))(H_(2)S)+Cl_(2) to underset(("Sulphur"))(2HCl)+S`
Use of chlorine:
1. Purification of drinking water
2. Bleaching of cotton textiles, paper and rayon
3. It is used in extraction of gold and platinum