Aromatic sulfonic acids are organic compounds that contain a sulfonic acid group (-SO₃H) attached to an aromatic ring. These compounds are known for their strong acidity and are commonly used in various industrial applications, including dyes, detergents, and pharmaceuticals. The presence of the aromatic ring enhances their stability and reactivity. One of the most well-known aromatic sulfonic acids is benzenesulfonic acid, which serves as a precursor for many chemical syntheses. Aromatic sulfonic acids can also act as surfactants, helping to reduce surface tension in liquids, making them valuable in cleaning products and emulsifiers.