Consider the following: 1. Oxides of Hydrogen 2. Oxides of Nitrogen 3. Oxides of Sulphur Which of the above causes/cause acid rain ?

1. Acid rain refers to precipitation (rain, snow, fog) that is unusually acidic due to atmospheric pollution. 2. The primary causes are emissions of Sulphur Dioxide (SO₂) and Nitrogen Oxides (NOx) from human activities, mainly the burning of fossil fuels. 3. These gases react with water, oxygen, and other chemicals in the atmosphere to form sulfuric acid (H₂SO₄) and nitric acid (HNO₃). 4. Therefore, Oxides of Nitrogen (2) and Oxides of Sulphur (3) are the direct precursors and causes of acid rain. 5. Oxides of Hydrogen (1), primarily water (H₂O), are necessary components for the formation of acids in the atmosphere but are not the pollutants that initiate the process. Water itself is not considered a cause of acid rain in this context. 6. Hence, only 2 and 3 cause acid rain.