🔍 Key Concepts

• Freon is a trade name for a family of halocarbon refrigerants (often chlorofluorocarbons, CFCs, or hydrochlorofluorocarbons, HCFCs). • These molecules are typically based on simple hydrocarbon chains that are then substituted with chlorine and fluorine atoms. • Think about which choices list small hydrocarbons that are actually used as the starting point for many halogenated refrigerants.

💭 Think About

• Look at each option and separate the hydrocarbons (like methane, ethane) from the other compounds (like ammonia, carbon dioxide, sulfur dioxide). Which ones are realistic bases for forming many different halogenated refrigerants? • Consider the general chemical pattern: many classic Freons are variants of very small alkanes (saturated hydrocarbons). Which answer includes those as the primary base molecules? • Ask yourself: are common Freon designations (like R‑12, R‑22, etc.) derived from modified methane/ethane structures or from ammonia/CO₂/SO₂ skeletons?

✅ Before You Answer

• Verify which compounds in the options are simple alkanes (single-bond hydrocarbons) commonly halogenated to form refrigerants. • Check which compounds in each pair are inorganic refrigerants (like ammonia, CO₂, SO₂) rather than the main base for Freon-type halocarbons. • Make sure the pair you select can logically be the primary parent molecules for most chlorofluorocarbon (CFC/HCFC) structures.