The abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen is ____.

The abbreviation that represents refrigerants containing chlorine, fluorine, carbon, and hydrogen is HCFC. The "H" stands for hydrogen, "C" for carbon, "F" for fluorine, and the second "C" indicates that chlorine is also present. HCFCs are a class of refrigerants that were developed to replace CFCs (chlorofluorocarbons), which are known for their ozone-depleting properties. HCFCs have lower ozone depletion potential compared to CFCs but are still being phased out due to their greenhouse gas effects.

In contrast, HFC stands for hydrofluorocarbons, which contain hydrogen, fluorine, and carbon but do not contain chlorine, which makes them less harmful to the ozone layer. CFC represents chlorofluorocarbons, which contain chlorine but are being phased out entirely due to their significant impact on ozone depletion. HFAC is not a recognized abbreviation in the context of refrigerants. Therefore, HCFC is the correct choice as it specifies the presence of both chlorine and hydrogen along with carbon and fluorine.