Question

Give reason for the following:

The formation of ozone involves a chemical reaction called photolysis.

Answer 1

With the help of UV rays
O₂ molecule breaks into two oxygen atoms called photolysis. 

\[\ce{O2 ->[UV][light] [O] + [O]}\]

Now more of O₂ molecule combine with [O]
O₂ + [O] → O₃ ozone