Acid rain (Formation and effects)

  • Various industrial gases like carbon dioxide, sulphur dioxide, sulphur trioxide, nitric oxide, nitrogen dioxide in reaction with water of the atmosphere form acids.
  • Those acids get mixed with rain and fall down in the form of rain, which is called acid rain.
  • Thus, the rain containing small amount of acids formed from gases like oxides of sulphur and nitrogen etc. present in the atmosphere is called acid rain.
  • The process of formation of acid rains in atmosphere occurs as follows:

Formation of sulphuric acid (H2SO4)

  • SO2 + O2 ——-> H2SO3
  • SO3 + H2O —–> H2SO4

Formation of Nitric acid (HNO3)

  • NO + O3 —-> NO2+ O2
  • 4NO2 + O2 —> N2O5
  • N2O5 + H2O —-> HNO3

Formation of Hydrocholoric acid (HCl)

  • Cl2 —> Cl+ Cl (chlorine free radicals)
  • H2O —> H+ + OH
  • H+ + Cl —> HCl

Formation of carbonic acid (H2CO3)

  • H2O + CO2 —> H2CO3


  • The acids like H2SO4, HNO3, HCl, H2CO3 get mixed with rain water and fall down on the earth in the form of acid rain.

Effects of acid rain:

  • Acid rain corrodes historical monuments like statue, sculptures of metals, marble stones etc.
  • It increases the acidity of soil and reduces the production of crops.
  • It also increases the acidity of water resources and may hamper aquatic life (aquatic plants and animals).
  • It causes different types of skin and respiratory tract diseases in human beings and other animals.
  • Acid rain damages a lot of crop plants and trees in the forest each year.

Acid rain (Formation and effects)