How is acid rain formed ? Explain its effect.

Explanation

Burning of fossile 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 acid respectively by the reaction with oxygen and water.
`2SO_(2) + O_(2) + 2H_(2)O rarr 2H_(2) SO_(4)`
`4NO_(2)+O_(2)+2H_(2)O rarr 4HNO_(3)`
The pH of rain water drops below the leve 5`:`6 and hence its is called acid rain.
Harmful effect of acid rain `:` Some harmful effects are dicussed 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) rarr CaSO_(4) + H_(2) O + COuarr`
(ii) Acid rain affects plants and animal life in aquatic acosystem.
(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.