The precipitation containing some acids such as sulphuric acid (H2S04) Nitric Acid (NH03), Hydrochloric Acid (Hcl) etc. is known as Acid Rain.
Causes of Acid Rain:
Nitrogen and Sulphur are released in the atmosphere due to burning of fossil fuel i.e. coal, petroleum etc. wood and emission from industries and vehicles. Nitrogen and sulphuric undergo oxidation to form nitric acid and sulphuric acid respectively.
2S02 + 02->2S04
2SO4 + H2->H2S04
2NO2 + 02->N205+O2
N2Os + H20->2HN03
The Acid rain has a pH of 5.5 or less.
The occurrence of Acid rain is more in a place where the uses of fuels are more and also having more industries and vehicles. The occurrence of acid rain is more is developed countries such as United Kingdom, Netherland etc. Japan, Germany, Canada, Sweden etc. In India the occurrence of Acid Rain is in Pune in Maharashtra, Trivandrum in Kerala and in Mumbai.
Effects of Acid Rain in Environment:
- Acid rain lowers the pH of water, of water reservoir such as pond, Lake River, sea etc. As a result the growth and reproduction of aquatic animals including fishes get disturbed and their growth is retarded.
- Acid rain caused lowering of soil PHz As a result, soil fertility decreases. The soil ecosystem gets disturbed due to change of flora acid fauna.
- Acid rain causes damages to the skin of animals and man.
- It has adverse effect on vegetation. It results in poor germination of seed suppression of growth leaf drops and reduction in production.
- Acid rain damaged buildings and structural materials of marble limestone, state etc. These materials become structurally weak as calcium carbonate reacts with sulphuric Acid to form soluble sulphate which is leached out by rain water.
CaCO3 + H2SO4 à CaSo4 + CO2 + H20
(Limestone) (Sulphuric (Calcium (carbon (Water)
Acid) Sulphate Dioxide)
In India Taj Mahal is threatened by acid rain from Mathura refinery and other industries this type of erosion is called store cancer.
- Acid rain causes pollution of water reservoirs and ecosystem gets disturbed due to death of aquatic animals.