Describe the preparation of Ozonised oxygen with an equation. Name the ozonised product obtained when the ozone reacts with lead-sulphide. 

Explanation

When a dry stream of oxygen is passed through a silent electrical discharge, conversion of oxygen to ozone `(10%)` occurs. The product is known as ozonised oxygen.
`2O_(3)overset(473K)underset("catalyst")rarr 3O_(2)`
Since the formation of ozone from oxygen is an endothermic process.
Ozone oxidises black lead sulphide to white lead sulphate. `PbS+4O_(3)rarr PbSO_(4)+4O_(2)`