Q . Why dry chlorine gas does not show bleaching property ?

Answer 1

when chlorine reacts with water (Moisture) then only it releases Nascent(Atomic form) oxygen. it is this nascent oxygen which bleaches(decolourises) the coloured matter due to oxidation. Dry chlorine cannot release nascent oxygen so bleaching action is not shown

The reaction is as follow :-

Cl₂ + H₂O --------> HCl + HOCl(HClO)

HClO ------------> HCl + [O]

Coloured substance + [O] -------> colourless substance