Answer : The gas formed is Ozone, [tex]O_3[/tex].
Explanation :
Ozone is the gas which is naturally formed in the stratosphere region.
There are two steps involved in the ozone formation :
Step 1 : The oxygen molecule breaks into two separate oxygen atoms in the presence of sunlight.
[tex]O_2\overset{h\nu}\rightarrow O+O[/tex]
Step 2 : These two separate oxygen atom further react with the oxygen molecule to produce ozone molecule.
[tex]O+O_2\rightarrow O_3[/tex]
The overall reaction is,
[tex]3O_2\overset{h\nu}\rightarrow 2O_3[/tex]
