Question

On the basis of chemical reactions involved, explain how do CFC’s cause depletion of ozone layer in stratosphere?

Answer 1

In the presence of uv radiation, CFC’s break up into chlorine free radical.

\[\ce{CF2Cl ->[hv] CF2Cl + Cl}\]

\[\ce{CFCl3 ->[hv] CFCl2 + Cl}\]

\[\ce{Cl + O3 → ClO + O2}\]

\[\ce{ClO + O → Cl + O2}\]

Chlorine radical is regenerated in the course of reaction. Due to this continuous attack of Cl thinning of Ozone layer takes place which leads to formation of the ozone hole.

It is estimated that for every reactive chlorine atom generated in the stratosphere 1,00,000 molecules of ozone are depleted.