Which substances are used in refrigerants and aerosol propellants?

• A. CFCs
• B. HCFCs
• C. HFCs
• D. PCBs

Answer: (A)

Chlorofluorocarbons (CFCs) were historically used in both refrigerants and aerosol propellants because of their stability, non-flammability, and practical properties for spraying and cooling. However, when released, they break down to release chlorine that depletes the ozone layer, leading to global agreements to phase them out and replace them with alternatives. While HCFCs and HFCs have taken their place as refrigerants, with HCFCs having less ozone depletion and HFCs having none, PCBs are not used as refrigerants or aerosol propellants at all; they were used as dielectric fluids in electrical equipment and are now heavily regulated due to toxicity. So the substances that fit the description best are CFCs.