Rainwater with a pH as low as 2.5 has been recorded in some parts of the
world . They are commonly known as acid rain .
Cause of acid rain:
Sulphur dioxide released from the burning of fossil fuels in power plants
and industrial plants is the primary cause of acid . In the atmosphere , sulphur
dioxide is slowly oxidized to sulphur trioxide which dissolves readily in water
droplets to form sulphuric(VI) acid .
Nitrogen oxides released from the burning of fossil fuels in automobiles
and power plants also cause the formation of acid rain . When released to the
atmosphere , nitrogen monoxide combines with atmospheric oxygen to form nitrogen
dioxide .In a series of complex reaction , nitrogen dioxide combines with oxygen
and water to form nitric(V) acid .
Effect on the environment:
-
In water of pH less than 4.5 , calcium metabolism in fresh water fish
will be affected , leading to poor health and stunted growth . As a result ,
diversity and population of some fresh water species will be reduced .
-
In soil of pH less than 4.5 , absorption of needed nutrients like potassium ,
calcium and magnesium ions by plants will be affected , often being replaced by
toxic aluminum ions , resulting in death of plants .
-
Acid rain corrodes metals and accelerates the deterioration of building , rock
and statue .
