The burning of coal releases SO2 into the atmosphere, where it turns into H2SO4, which is a strong diprotic acid. This sulphuric acid returns to the surface of the earth through rain, hence acid rain. The following (from wikipedia) shows the transformation of SO2 into H2SO4. In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via an intermolecular reaction [5]: SO2 + OH· ? HOSO2· which is followed by: HOSO2· + O2 ? HO2· + SO3 In the presence of water, sulfur trioxide (SO3) is converted rapidly to sulfuric acid: SO3 (g) + H2O (l) ? H2SO4 (l) The limestone basin lake can still contain life, because limestone contains a lot of calcium carbonate. Calcium carbonate neutralizes acids according to the following reaction: CaCO3 (s) + H2SO4 (aq) <-> CaSO4 (aq) + CO2 (g) + H2O (l) (CaCO3 is basic) Hence, the limestone basin reduces the lakes acidity. Clay consists of minute charged particles. According to chemistryquestion.com \"Clay in soil has a property of ion exchange. Under acidic conditions, H+ is adsorbed on the surface of clay and Ca2+ etc. are eluted instead.\" Or as elmhurst.edu puts it \"The hydrogen ions in the sulfuric acid trade places with the metal ions. The hydrogen ions are retained and neutralized by the soil.\" Hence, clay maintains a high concentration of H+, which makes life impossible. Solution The burning of coal releases SO2 into the atmosphere, where it turns into H2SO4, which is a strong diprotic acid. This sulphuric acid returns to the surface of the earth through rain, hence acid rain. The following (from wikipedia) shows the transformation of SO2 into H2SO4. In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via an intermolecular reaction [5]: SO2 + OH· ? HOSO2· which is followed by: HOSO2· + O2 ? HO2· + SO3 In the presence of water, sulfur trioxide (SO3) is converted rapidly to sulfuric acid: SO3 (g) + H2O (l) ? H2SO4 (l) The limestone basin lake can still contain life, because limestone contains a lot of calcium carbonate. Calcium carbonate neutralizes acids according to the following reaction: CaCO3 (s) + H2SO4 (aq) <-> CaSO4 (aq) + CO2 (g) + H2O (l) (CaCO3 is basic) Hence, the limestone basin reduces the lakes acidity. Clay consists of minute charged particles. According to chemistryquestion.com \"Clay in soil has a property of ion exchange. Under acidic conditions, H+ is adsorbed on the surface of clay and Ca2+ etc. are eluted instead.\" Or as elmhurst.edu puts it \"The hydrogen ions in the sulfuric acid trade places with the metal ions. The hydrogen ions are retained and neutralized by the soil.\" Hence, clay maintains a high concentration of H+, which makes life impossible..