Sulfonic acid is a type of organic compound that contains a sulfonic group, which is characterized by a sulfur atom bonded to three oxygen atoms and one carbon atom. This functional group is represented as -SO₃H. Sulfonic acids are known for their strong acidity and are commonly used in the production of detergents, dyes, and pharmaceuticals. One of the most well-known sulfonic acids is benzenesulfonic acid, which is derived from benzene. Sulfonic acids are also important in the field of chemistry for synthesizing various compounds and are utilized in industrial applications due to their ability to act as strong acids and surfactants.