Chlorofluorocarbons CFCs are a class of compounds that contain carbon, chlorine, and fluorine atoms. They were widely used as refrigerants, propellants, and solvents in the past. However, it was discovered that CFCs contribute significantly to the depletion of the ozone layer, which protects the Earth from harmful ultraviolet UV radiation.The depletion of the ozone layer by CFCs occurs through a series of chemical reactions in the stratosphere. Here's a simplified explanation of the process:1. CFCs are released into the atmosphere and eventually reach the stratosphere, where they are exposed to UV radiation. The UV radiation breaks the CFC molecules, releasing chlorine atoms:CFC + UV radiation Cl chlorine atom + other products2. The chlorine atoms then react with ozone O3 molecules, breaking them apart into oxygen molecules O2 and chlorine monoxide ClO :Cl + O3 ClO + O23. The chlorine monoxide ClO can then react with another ozone molecule, releasing an oxygen molecule O2 and regenerating the original chlorine atom:ClO + O3 Cl + 2O24. The regenerated chlorine atom can then continue to react with more ozone molecules, leading to a chain reaction that results in the depletion of the ozone layer.The overall reaction for the ozone depletion process can be represented as:2O3 3O2This process continues until the chlorine atom is removed from the stratosphere by other chemical reactions or is transported back to the Earth's surface. The long lifetime of CFCs in the atmosphere and the ability of a single chlorine atom to destroy thousands of ozone molecules make CFCs a significant contributor to ozone depletion. As a result, the production and use of CFCs have been phased out under the Montreal Protocol, an international agreement designed to protect the ozone layer.