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Prelims 2021 paper

UPSC CSE Prelims 2021 · Question 18 · Pollution & waste

With reference to furnace oil, consider the following statements: It is a product of oil refineries.

Prelims 2021 · Q18

Pollution & waste Easy

With reference to furnace oil, consider the following statements:

  1. 1.It is a product of oil refineries.
  2. 2.Some industries use it to generate power.
  3. 3.Its use causes sulphur emissions into environment.

Which of the statements given above are correct?

Answer & explanation

Answer: (d) 1, 2 and 3

Furnace oil is a heavy residual fuel left after the lighter fractions are distilled from crude oil in a refinery. Industries burn it in boilers, furnaces and captive power plants, and because it is rich in sulphur, burning it releases sulphur dioxide. All three statements hold.

  • ✓ 1. It is the heavy residue that remains after refineries distil off the lighter products, which is why it is also called residual fuel oil.
  • ✓ 2. Heavy fuel oil is used to produce electric power and for many industrial heating purposes, including captive generation.
  • ✓ 3. Burning oil that contains sulphur emits sulphur dioxide, and furnace oil is among the higher-sulphur fuels, so its use adds SO2 to the air.

Remember · Furnace oil = heavy residual refinery product; burnt in industrial boilers and power units; high sulphur, so a source of SO2.

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·

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