answer: (b) Only two.
Explanation:
Hydrofluorocarbons (HFCs) are used in the making of two of the listed items:
Foam agents: HFCs are used as blowing agents in the production of foam. They help create the foam structure by generating gas bubbles within the material.
Fire retardants: HFCs can be used as fire suppressants or fire extinguishing agents due to their ability to rapidly absorb heat and reduce the temperature of the fire.
Aerosols and lubricants do not typically use hydrofluorocarbons in their production. However, it is worth noting that some aerosols may contain hydrofluorocarbon propellants, but the aerosols themselves are not made using HFCs.
Reference source:
The information provided is based on the knowledge cutoff of September 2021. As an AI language model, I don't have direct access to external sources such as NCERT books or specific websites. However, you can refer to the relevant sections or chapters in NCERT textbooks on chemistry or environmental science to find more detailed information about hydrofluorocarbons and their applications. Additionally, you can visit the official websites of government organizations such as the Ministry of Environment, Forest and Climate Change (www.moef.gov.in) or international organizations like the United Nations Environment Programme (www.unep.org) for comprehensive information on HFCs and their uses.
