(i) The chioro-Iluoro derivatives of methane and ethane are named Freons (CFC’s). They slowly pass from troposphere to stratosphere. They stay for a very longer period of about 50-100 years. In the presence of UV radiations, CFC’s break up into chienne free radical
\(Cl{\bullet} + O_3 \longrightarrow {ClO}^{\bullet} + O_2\)
\(ClO{\bullet}\) + O \(\longrightarrow\) \({Cl}^{\bullet}\) + O2
(iii) Chlorine radical is regenrated in the course of the reaction. Due to this continuous attack of Cl free radicals, thinning of ozone layer takes place which leads to the formation of ozone hole.
(iv) Li is estimated that for every reactive chlorine atom generated in the stratosphere 1,00,000 molecules of ozone are depleted
