UV radiation from sun causes a reaction that produces

Ozone in the stratosphere is a product of UV radiations acting on dioxygen (O2) molecules. The UV radiations split apart molecular oxygen into free oxygen (O) atoms. These oxygen atoms combine with the molecular oxygen to form ozone.O2 (g) →UVO(g) + O(g) ; O(g) + O2 (g) ⇌UVO3 (g)