Question 20
1. Aerosols
2. Foam agents
3. Fire retardants
4. Lubricants
In the making of how many of the above are hydrofluorocarbons used?
AOptions
BSolution
Hydrofluorocarbons (HFCs) are potent greenhouse gases that were widely adopted as substitutes for ozone-depleting substances like CFCs and HCFCs, primarily in refrigeration and air conditioning. Let's examine their uses in the given options:
1. Aerosols: HFCs are commonly used as propellants in various aerosol products, including medical inhalers and some consumer aerosols.
2. Foam agents: HFCs are used as blowing agents in the production of foams (e.g., insulation foams, packaging foams) to create their cellular structure.
3. Fire retardants: Some HFCs, particularly those like HFC-227ea (also known as FM-200), are used as gaseous fire suppression agents in fire protection systems.
4. Lubricants: HFCs themselves are generally not used as lubricants. Lubricants are typically oils, greases, or other substances designed to reduce friction between moving parts. While some specialized lubricants might contain fluorine, HFCs are primarily known for their refrigerant, propellant, or blowing agent properties, not as lubricants.
Therefore, HFCs are used in aerosols, foam agents, and fire retardants. So, 'Only three' is the correct answer.
CStrategy
For questions on chemicals and their applications, understand the primary functions and common uses of a substance. HFCs are well-known for their role as refrigerants and propellants. If an option seems unrelated to these primary functions or known secondary uses, scrutinize it carefully.
DSyllabus Analysis
This question falls under 'Environment and Ecology' (Pollutants/Chemicals) and 'Science & Technology' (Industrial Applications) in the UPSC Prelims syllabus.
EQuestion Analysis
Medium. Requires knowledge of the industrial applications of HFCs, specifically differentiating common uses from uncommon or incorrect ones.