Which chemical damages the protective ozone layer?
There are a lot of chemicals that damage the ozone layer, the most notorious (and the one you most likely have in mind) is chlorofluorocarbons (CFCs).
Chlorofluorocarbons (CFCs) are an organic compound composed of chlorine, fluorine, and carbon (hence its namesake). CFCs are volatile compounds meaning that they rise into the atmosphere or evaporate when exposed to the air. They were used as refrigerants, solvents, and propellants. CFCs, are now being phased out of production because of how readily they damage the ozone layer.