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?
Show answer
Answer: C. Hydrofluorocarbons (HFCs) are used as aerosol propellants, as foam-blowing agents and in fire suppressants (fire retardant systems), besides refrigeration and air-conditioning. They are not a standard ingredient in lubricants. So only three.
Watch for: Refrigeration oils are used with HFC gases, which tempts students to count lubricants too.
Why the other options are wrong
- A. Wrong because HFCs are used in more than one of these.
- B. Wrong because HFCs are used in aerosols, foams and fire suppression.
- D. Wrong because HFCs are not used to make lubricants.
Source to check: UNEP Ozone Secretariat, Kigali Amendment to the Montreal Protocol materials; US EPA, 'Recent International Developments under the Montreal Protocol' (HFC uses)
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.