Chemical weathering is the decomposition and disintegration of rock due to chemical reactions. According to Eastern Illinois University, chemical agents break down the bonds holding rocks together, causing the rocks to fall apart, forming smaller and smaller pieces over time. Chemical weathering includes dissolution, oxidation and hydrolysis.
Natural acidic waters or pollutants dissolve rock and allow additional water to gain access, causing karsts and sinkholes to form. Dissolution is especially common in areas rich in limestone. Oxidation takes place when oxygen combines with elements in rocks, such as ferrous iron. An oxidation reaction occurs, forming new rock types, which are often much softer and are easier to break apart. Hydrolysis occurs when water combines with elements in rocks, such as silicate minerals. Like in oxidation, these hydrolysis reactions form softer rock types that are more easily broken apart.