Sulfonic acids are a class of organic compounds characterized by the presence of a sulfonic group (-SO₃H). This functional group consists of a sulfur atom bonded to three oxygen atoms and a hydrogen atom. Sulfonic acids are typically strong acids and are soluble in water, making them useful in various chemical applications. These compounds are commonly used in the production of detergents, dyes, and pharmaceuticals. One well-known example is benzenesulfonic acid, which serves as a precursor in the synthesis of many industrial chemicals. Their unique properties make sulfonic acids valuable in both laboratory and industrial settings.