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?

(a) Only one

(b) Only two

(c) Only three

(d) All four

10. Ans: c

Explanation: 

Only in the making of the first three Hydrofluorocarbons (HFCs) are used.

About Hydrofluorocarbons (HFCs)

These are a group of synthetic gases primarily used for cooling and refrigeration. Many HFCs are very powerful, short-lived climate pollutants with an average atmospheric lifetime of 15 years.

HFCs are entirely human-made. They are primarily produced for use in refrigeration, air-conditioning, insulating foams and aerosol propellants, with minor uses as solvents and for fire protection. (Hence1,2,3 are correct) .

However, while HFCs have an ozone depletion potential of zero, they are potent greenhouse gases, and thus their manufacture and use became increasingly regulated in the 21st century.

As refrigerants, HFCs are used in a wide variety of cooling systems, from refrigerators and freezers to automotive air-conditioning units. HFCs are also used as blowing agents in the production of polymer foams; as firefighting agents (having replaced halons); as solvents in cleaning products for plastics and metals and in plasma etching for semiconductor technology; and as propellants in metred-dose inhalers prescribed for the treatment of asthma.

Lubricating oils are composed of 80–90% petroleum hydrocarbon distillate with 10–20% additives to impart specific properties to the oil. The petroleum hydrocarbon distillate generally consists of paraffinic or naphthenic compounds. They do not involve use of HFCs in their making. They are made from hydrocarbons.(Hence 4 is wrong)

About Hydrocarbons:

• Hydrocarbon is a class of organic chemical compounds composed only of the elements carbon (C) and hydrogen (H). 
• The carbon atoms join together to form the framework of the compound, and the hydrogen atoms attach to them in many different configurations. 
• Hydrocarbons are the principal constituents of petroleum and natural gas. 
• They serve as fuels and lubricants as well as raw materials for the production of plastics, fibres, rubbers, solvents, explosives, and industrial chemicals.

Read: Previous Year UPSC Environment Questions (PYQs) With Explanation 2023