Question

How do CFCs destroy ozone? What steps have been taken to save
ozone layer? Are they safe?

Answer 1

The Cl atoms of chlorofluoro carbons can destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, a chlorine atom reacts with an ozone molecule, taking an oxygen atom with it (forming ClO) and leaving a normal oxygen molecule. The chlorine monoxide (i.e., the ClO) can react with a second molecule of ozone (i.e., O3) to yield another chlorine atom and two molecules of oxygen. The chemical shorthand for these gas-phase reactions is:

Cl + O3 → ClO + O2 – The chlorine atom changes an ozone molecule to ordinary oxygen

ClO + O3 → Cl + 2O2 – The ClO from the previous reaction destroys a second ozone molecule and recreates the original chlorine atom, which can repeat the first reaction and continue to destroy ozone.

The overall effect is a decrease in the amount of ozone.