Consider the following :
- 1.Carbon monoxide
- 2.Nitrogen oxide
- 3.Ozone
- 4.Sulphur dioxide
Excess of which of the above in the environment is/are cause(s) of acid rain ?
Show answer
Answer: B. Acid rain forms when sulphur dioxide and nitrogen oxides react with water in the air to make sulphuric and nitric acids. Carbon monoxide and ozone are pollutants but are not the main causes of acid rain. So 2 and 4 only.
Watch for: Students include every harmful gas; only SO2 and NOx form the acids in acid rain.
Why the other options are wrong
- A. Wrong because carbon monoxide and ozone are not causes of acid rain, and SO2 is missing.
- C. Wrong because nitrogen oxides are also a cause.
- D. Wrong because carbon monoxide and ozone do not cause acid rain, and NOx is missing.
Source to check: NCERT Class 11 Chemistry, Chapter 14 (Environmental Chemistry), section on acid rain
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.