UPSC Prelims 2021 · GS Paper I
Question 18: Environment and Ecology
With reference to furnace oil, consider the following statements :
- 1.It is a product of oil refineries.
- 2.Some industries use it to generate power.
- 3.Its use causes sulphur emissions into environment.
Which of the statements given above are correct?
AnswerUPSC’s answer is (d).
Furnace oil is a heavy residual fuel left after crude oil is refined, so it is a product of oil refineries. Industries burn it in boilers and furnaces, and some use it to generate power. It has a high sulphur content, so burning it releases sulphur dioxide, which contributes to air pollution and acid rain. Remember: furnace oil is a cheap, dirty refinery residue.
- 1. It is a heavy residue from refining crude oil.
- 2. Some industries burn it to generate power.
- 3. It is high in sulphur, so burning it releases sulphur emissions.
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: It is a heavy residue from refining crude oil.
- Then, if you were sure statement 2 is correct, (c) goes: it leaves 2 out.
What you needed to know: Some industries burn it to generate power.
- Then, if you were sure statement 3 is correct, (a) goes: it leaves 3 out.
What you needed to know: It is high in sulphur, so burning it releases sulphur emissions.
Only (d) is left. This one needs every statement.
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 omits statement 3; furnace oil emits sulphur.
- (b) Wrong: it omits statement 1; furnace oil is a refinery product.
- (c) Wrong: it omits statement 2; some industries do use it for power.
- (d) Right: all three statements are correct.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper I, Series A. The paper on upsc.gov.in.