How do chlorofluorocarbons destroy ozone?

1 Answer
May 14, 2018

UV radiation in the atmosphere causes an initial bond cleavage that creates free radical centres.....


UV induced cleavage of the C-Cl bond in the chlorofluorocarbon molecule forms a free radical centre in the molecule plus a chlorine atom. The chlorine atom reacts with ozone to form oxygen and Cl-O.

#Cl + O_3→ClO + O_2#

Cl-O also is able to react with ozone, thereby removing another oxygen atom plus a chlorine atom.....

#ClO + O.→Cl + O_2#

And the oxygen atom can then react with ozone to form more oxygen (molecules).

#O_3 + O.→ 2O_2#

So not only can CFC's in the atmosphere react with and depelet ozone, but they react so as to cause the formation of other species that also react with and deplete ozone.

As a result, a single CFC molecule can cause the breakdown of thousands of ozone molecules.