How Acid rain is formed equations? Formation of acid rain:Sulphur dioxide accounts for most of the acid rain problems. (a) When sulphur dioxide dissolves in water, sulphurous acid is formed. SO2(g) + H2O(l) → H2SO3(aq) (b) Sulphur dioxide can react with oxygen and water to form sulphuric acid. 2SO2(g) + O2(g) + 2H2O(I) → 2H2SO4(aq) Acid rain occurs when the pH of … [Read more...] about How Acid rain is formed equations?