Q. Consider the following:
  1. Aerosols
  2. Foam agents
  3. Fire retardants
  4. Lubricants
In the making of how many of the above are hydrofluorocarbons used? (UPSC Prelims 2023)

Answer: Only three
Notes: The correct answer is [C] Only three, according to the official UPSC answer key. While HFCs have technical applications in many fields, their primary industrial use as defined in environmental regulatory frameworks (like the Montreal Protocol) focuses on specific sectors.The distinction hinges on whether the HFC is a constituent/process agent of the product or merely a compatible fluid. For aerosols, foam, and fire suppressants, the HFC is an integral functional component of the final product or its manufacturing process. In the case of lubricants, HFCs are the substances being lubricated in a system, rather than a raw material for the lubricant's production.