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?
Correct Answer C. Only three
Explanation
Items 1, 2, and 3 are correct: Hydrofluorocarbons (HFCs) were developed under the Montreal Protocol regime as non-ozone-depleting replacements for CFCs and HCFCs. They are widely used as aerosol propellants, blowing agents in insulating foams, and clean gaseous fire retardants/suppressants in enclosed electrical rooms.
Item 4 — Incorrect: HFCs are not used as base lubricants. Commercial lubrication depends on mineral oils, polyalphaolefins, or synthetic esters that provide high viscosity and lubricating film strength.