On addition of ozone gas to KI solution, violet vapours are obtained. Why ?

How does Ozone react with KI solution ?

A metal nitrate reacts with KI solution to give a black precipitate which on addition of excess of KI solution forms an orange coloured solution. The cation of metal nitrate is :

A metal nitrate reacts with KI solution to give a block precipitate which on addition of excess of KI solution forms an orange coloured solution. The cation of metal nitrate is :

The addition of Br_(2) to NaI turns the solution violet.

Is vapour and gas same? Why?