How many groups of halocarbons are there?

Halocarbons are organic compounds that contain carbon and halogen atoms, and they are categorized into three primary groups based on their structure and the number of halogen atoms they contain. These groups are:

1. Chlorofluorocarbons (CFCs) - These are used in refrigeration and air conditioning, as well as in foam-blowing agents and aerosol propellants. They are known for their role in ozone depletion.

2. Hydrochlorofluorocarbons (HCFCs) - These are considered transitional substitutes for CFCs and have fewer negative effects on the ozone layer, though they still contribute to its depletion.

3. Hydrofluorocarbons (HFCs) - These do not contain chlorine and therefore do not damage the ozone layer. They are mainly used in refrigerants and are considered more environmentally friendly alternatives to CFCs and HCFCs, though they are still potent greenhouse gases.

This classification underscores the environmental impact of different halocarbon groups and their regulation under various international protocols, such as the Montreal Protocol. Thus, the correct answer outlines the fundamental understanding of halocarbon classification in the context of industrial refrigeration.