Chlorofluorocarbons CFCs are compounds containing carbon, chlorine, and fluorine atoms. They were widely used as refrigerants, propellants, and solvents in the past. However, it was discovered that CFCs have a detrimental effect on the ozone layer in the stratosphere, leading to the formation of the ozone hole. The chemical reaction that occurs between CFCs and ozone molecules can be described as follows:1. Photodissociation of CFCs: When CFCs reach the stratosphere, they are exposed to ultraviolet UV radiation, which causes them to break down and release chlorine atoms. For example, the photodissociation of CFC-12 CCl2F2 can be represented as:CCl2F2 + UV CClF2 + Cl2. Chlorine atom reacts with ozone: The released chlorine atoms are highly reactive and can react with ozone O3 molecules, forming chlorine monoxide ClO and molecular oxygen O2 :Cl + O3 ClO + O23. Chlorine monoxide reacts with atomic oxygen: The ClO formed in the previous step can react with atomic oxygen O to regenerate the chlorine atom and produce molecular oxygen:ClO + O Cl + O2The regenerated chlorine atom can then react with another ozone molecule, repeating steps 2 and 3. This catalytic cycle can continue for a long time, with a single chlorine atom being responsible for the destruction of thousands of ozone molecules.The overall reaction for the destruction of ozone by CFCs can be represented as:O3 + O 2 O2The loss of ozone molecules in the stratosphere leads to the thinning of the ozone layer, which is essential for protecting life on Earth from harmful UV radiation. This is why the production and use of CFCs have been phased out under the Montreal Protocol, an international treaty designed to protect the ozone layer.