CBSE Class 12-science Answered

Chlorofluorocarbons (CFCs) are compounds containing only carbon, chlorine and fluorine (no hydrogen). 
Chlorofluorocarbons (CFCs) are sold under the trade name of Freons.
In the stratosphere, CFCs come into contact with short wavelength ultraviolet radiation which is able to split off chlorine atoms from the CFC molecules

CCl3F(g)

u.v radiation --------------->

CCl2F(g)

+

Cl(g)

These chlorine atoms destroy the ozone layer

Cl(g)

+

O3(g)

------------->

ClO(g)

+

O2(g)

There are significant numbers of oxygen atoms in the stratosphere (since ozone undergoes a natural photochemical decomposition producing oxygen atoms and molecules) which leads to the regeneration of chlorine atoms in the stratosphere.So, 1 CFC molecule can destroy many ozone molecules.

ClO(g)

+

O(g)

------------->

O2(g)

+

Cl(g)