Acid rain is formed when rain water has a pH of about 5.2 or below. It is caused by the presence of the oxides of nitrogen or sulphur in air. These oxides dissolve in rain water to form the corresponding mineral acids thereby decreasing the pH of rainwater.
If we look at the reaction;
2NO2 + H2O ---> HNO2 + HNO3
We will discover that the bonds broken are the bonds between;
