Acid rain is the rain water containing sulphuric acid and nitric acid ( alongwith small amount of hydrochloric acid ) which are formed from the oxides of sulphur and nitrogen present in the air as pollutant and has a pH of 4 - 5.
<b> Formation of Acid Rain :-</b> Due to natural sources such as bacterial action or volcanic eruption or due to human activities mainly involving combustion of fuel like coal, wood, petroleum products etc. Or from chemical industries, oxides of nitrogen and those of sulphur enet into atmosphere as a pollutants. The oxides of nitrogen undergo oxidation reactions. This reaction form a nitric acid . Thus, nitric acid comes down to the earth alongwith rain or react s with the bases like ammonia and lime to form nitrates.
<b> Harmful Effect of Acid Rain :- </b>
1. Acid rain causes extensive damages to buildings, statues and sculptural material, especially those made of marble, lime stone, slate, mortar etc. For example, Taj Mahal at Agra, Which is a very popular historical monument made of marble is being attacked by acid rain due to high concentration of oxides of sulphur and nitrogen in the air over Agra because of a large number of industries in the surrounding areas which are emitting these gases. As a result, marble is being eaten up causing pitting and discoloring and making it lustreless.
2. It also damages iron and steel structure.
3. It corrodes water pipes. As a result, heavy metals like iron, lead, copper are leached into drinking water which have toxic effects.
4. Acid rain increases the acidity of water in the lakes which is lethal for the fishes. For this reason, some of the lakes have become fishless. Thus it has greatly affected the fish population.
5. Acid rain damages leaves of trees and plants and retards the growth of forests. It also retards the growth of certain crops such as peas, beans, potato, raddish, carrot, spinach etc.
<b> Method of Reducing Acid Rain :-</b> Acid rain is due to emission of sulphuric dioxide and nitroge dioxide in the atmosphere. Therefore, to reduce the formation of acid rain, the emission of these gases has to be controlled. The following steps may be taken as :-
1. By using less vehicles driven by fossil fuels.
2. By using less sulphur content fossil fuels for power plants and industries, e.g., by using natural gas which is a better fuel than coal or using natural gas which is a better fuel than coal or using coal with less sulphur content.
3. By using catalytic converters in cars so that oxides of nitrogen present in exhaoust gases is converted intonitrogen at 573 K.
4. By adding powdered limestone to neutralize the acidity of soil.
No comments:
Post a Comment