Question

Identify the acidic oxides responsible for acid rain. State how their presence results in formation of acid rain. Give a reason why acid rain damages heritage buildings.

Answer 1

Basic reactions for products formed in acid rain

1. Sulphuric impurities in coal – form pollutant sulphur dioxide [SO₂] and sulphur trioxide [SO₃]
   Sulphur dioxide + water vapour → Sulphurous acid [H₂SO3]
   Sulphur trioxide + water vapour→ Sulphuric acid [H₂SO₄]
2. Nitrogen in air at high temperatures form pollutant nitric oxide [NO] and nitrogen dioxide [NO₂]
   Nitric oxide + oxygen → nitrogen dioxide [NO₂] Nitrogen dioxide + water → Nitrous acid [HNO₂] and Nitric acid [HNO3]
   Acid rain corrodes metallic surfaces & weakens building materials such as statues, marble, limestone [CaCO₃] etc. It causes damage to heritage structures such as the Taj Mahal, which is predominantly made of lime stone and reacts with acids present in acid rain.