Question

Name the common refrigerant. How does it deplete the ozone layer?

Answer 1

The main refrigerants used are Freon chlorofluorocarbons (CFC).

They deplete the ozone layer.

1. The chlorofluorocarbons are decomposed by ultraviolet rays to highly reactive chlorine, which is produced in the atomic form.
   \[\ce{CF2Cl2_{(g)}  ->[ultraviolet] CF2Cl_{(g)} + Cl_{(g)}}\]
2. The free radical \[\ce{[Cl]}\] reacts with ozone, and chlorine monoxide is formed.
   \[\ce{Cl_{(g)} + O3_{(g)} -> ClO_{(g)} + O2_{(g)}}\]
   This causes depletion of ozone.
3. This causes depletion of the ozone layer, and chlorine monoxide so formed reacts with atomic oxygen and produces more chlorine free radicals.
   \[\ce{ClO_{(g)} + O_{(g)} -> Cl_{(g)} + O2_{(g)}}\]

Again this free radical destroys ozone, and the process continues, thereby giving rise to ozone depletion.