Which of the following refrigerants is known by the designation R-12?

R-12 is known as a chlorofluorocarbon (CFC), which is a group of compounds that contain chlorine, fluorine, and carbon. CFCs like R-12 were commonly used as refrigerants in various applications because of their effective thermodynamic properties and stability. However, the environmental impact of CFCs, particularly their contribution to ozone depletion, led to a significant reduction in their use and the phasing out of many CFCs, including R-12.

The choice of chlorofluorocarbon as the designation for R-12 reflects its chemical structure and the fact that it falls within a category of refrigerants that have historically been used extensively in refrigeration and air conditioning systems before environmental regulations began to restrict their use. Understanding the classification and properties of refrigerants like R-12 is important for operating engineers to ensure compliant and safe handling of refrigerants in accordance with modern standards and regulations.