Q1. [1] straightforward initial-understanding
Which of the following correctly describes why fuels such as coal and petroleum are considered environmental pollutants when burned?
(A) They release only carbon dioxide, which is harmless.
(B) They contain nitrogen and sulphur, whose combustion produces oxides that pollute the air.
(C) They produce water vapour that causes acid rain.
(D) They burn with a clean blue flame that depletes oxygen rapidly.
- A They release only carbon dioxide, which is harmless.
- B They contain nitrogen and sulphur, whose combustion produces oxides that pollute the air.
- C They produce water vapour that causes acid rain.
- D They burn with a clean blue flame that depletes oxygen rapidly.
Generated by claude-sonnet-4-6 · 2026-06-26 01:06 · grounding rag
Model Answer
(B) They contain nitrogen and sulphur, whose combustion produces oxides that pollute the air.
Explanation
The textbook explicitly states: "Fuels such as coal and petroleum have some amount of nitrogen and sulphur in them. Their combustion results in the formation of oxides of sulphur and nitrogen which are major pollutants in the environment." Options A, C, and D are factually incorrect as per the source. This is a direct recall question — memorise the exact reason.
Source: Chapter 4, Section 4.3.1 (Combustion)