The correct answer is option 3: Chlorofluoro hydrocarbon.
Freon is a trade name for a type of refrigerant that was commonly used in various cooling systems such as air conditioners and refrigerators. The chemical composition of Freon consists of chlorine, fluorine, and carbon.
Option 1: Chlorinated hydrocarbon. While Freon does contain chlorine, it is not solely composed of chlorine and hydrocarbons. It also contains fluorine and carbon, making this option incorrect.
Option 2: Fluorinated hydrocarbon. This option is partially correct because Freon does contain fluorine and carbon. However, it also contains chlorine, so the complete chemical name of Freon is not solely a "fluorinated hydrocarbon."
Option 3: Chlorofluoro hydrocarbon. This is the correct answer because it accurately represents the chemical composition of Freon. It contains both chlorine and fluorine, making it a chlorofluoro hydrocarbon.
Option 4: Fluorinated aromatic compound. This option is incorrect because aromatic compounds are characterized by a specific ring structure, which is not present in Freon.
In summary, Freon, used as refrigerants, is chemically known as a chlorofluoro hydrocarbon.