How is acid rain formed ? Explain its effect.

Answer

Burning of fossil fuels (coal and oil) in power stations, furnaces and petrol, diesel in motor engines produce sulphur dioxide and nitrogen oxides. The main contributors of acid rain are `SO_(2) and NO_(2)` . They are converted into sulphuric acid and nitric respectively by the reaction with oxygen and water
`2SO_(2) + O_(2) + 2H_(2)O to 2H_(2) SO_(4)`
`4NO_(2) +O_(2) + 2H_(2) O to 4HNO_(3)`
The pH of rain water drops to 5: 6 and hence its is called acid rain .
Harmful effects of acid rain : Some harmful effects are discussed below .
(i) Acid rain causes extensive damage to buildings and structural materials of marbles. This attack on marble is termed as Stone leprosy.
`CaCO_(3) + H_(2) SO_(4) to CaSO_(4) + H_(2)O + CO2uarr`
(ii) Acid rain affects plants and animal life in aquatic ecosystem.
(iii) It is harmful for agriculture, trees and plants as it dissolves and removes the nutrients needed for their growth.
(iv) It corrodes water pipes resulting in the leaching of heavy metals such as iron, lead and copper into the drinking water which have toxic effects .
(v) It causes respiratory ailment in humans and animals .