Give reason for the bleaching action of `Cl_(2)`.

Explanation

In presencee of moisture or in aqueous solution, `Cl_(2)` libertes nascent oxygen.
`Cl_(2) + H_(2)O rarr 2 HCl underset("Nascent oxygen")([O])`
This nascent oxygen brings about the oxidation of coloured substances present in vegetable and organic matter to colourless substances.
Coloured substance + O `rarr` Colourless substance
Thus, the bleaching action of `Cl_(2)` is due to oxidation. Since the bleaching effect of `Cl_(2)` is permanent, it is used to bleach cotton and textiles and wood pulp for manufacture of paper and rayon.