UPSC Prelims 2012 · GS Paper I
Question 17: Environment and Ecology
Consider the following statements : Chlorofluorocarbons, known as ozone-depleting substances, are used
- 1.in the production of plastic foams
- 2.in the production of tubeless tyres
- 3.in cleaning certain electronic components
- 4.as pressurizing agents in aerosol cans
Which of the statements given above is/are correct?
AnswerUPSC’s answer is (c).
Chlorofluorocarbons were used as blowing agents in plastic foams, as solvents to clean electronic components, as aerosol propellants and as refrigerants. They are not used in making tubeless tyres. Their chlorine destroys stratospheric ozone, which is why the Montreal Protocol phases them out. Remember the uses: foam, solvents, aerosols, refrigerants.
- 1. CFCs served as blowing agents in plastic foams.
- 2. CFCs have no role in making tubeless tyres.
- 3. CFCs were used as solvents for cleaning electronic components.
- 4. CFCs were widely used as aerosol propellants.
How you could have got this
- If you were sure statement 1 is correct, (b) goes: it leaves 1 out.
What you needed to know: CFCs served as blowing agents in plastic foams.
- Then, if you were sure statement 2 is not correct, (a) and (d) go: each of them includes 2.
What you needed to know: CFCs have no role in making tubeless tyres.
Only (c) is left. You didn’t need statements 3 or 4.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: it includes tubeless tyres and omits aerosol propellants.
- (b) Incomplete: CFCs were also used in foams and for cleaning electronics.
- (c) Correct: foams, electronics cleaning and aerosols; not tubeless tyres.
- (d) Wrong: CFCs are not used in producing tubeless tyres.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2012, General Studies Paper I, Series A. The paper on upsc.gov.in.