Question 15
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.
Acidic oxides responsible for acid rain are:
- Oxides of Sulphur — Sulphur dioxide [SO2]
- Oxides of Nitrogen — Nitrogen dioxide [NO2]
Formation of acid rain:
The acidic oxides of Sulphur and Nitrogen combine with water vapour in presence of sunlight forming the respective acids.
Sulphur dioxide + water vapour ⟶ Sulphurous acid [H2SO3]
Sulphur trioxide + water vapour ⟶ Sulphuric acid [H2SO4]
Nitric oxide + oxygen ⟶ nitrogen dioxide [NO2 ]
Nitrogen dioxide + water ⟶ Nitrous acid [HNO2] & Nitric acid [HNO3]
Presence of these acids causes acid rain.
Damage to heritage buildings:
Acid rain damages heritage buildings as it 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 made of limestone and reacts with acids present in acid rain.