ClSO2OH

Chlorosulfonic acid, with the chemical formula ClSO2OH, is a highly corrosive and fuming liquid. It is an inorganic compound that can be considered a mixed anhydride of sulfuric acid and hydrochloric acid. Its appearance is typically a colorless to pale yellow liquid.

ClSO2OH is a strong acid and a powerful dehydrating agent. It reacts violently with water, producing sulfuric acid and hydrochloric acid, accompanied by significant heat generation. This reaction can cause splashing and hazardous fumes. Due to its reactivity, it is often used in organic synthesis for various reactions, including sulfonation and the introduction of sulfonyl chloride groups. It is also employed in the production of detergents, dyes, and pharmaceuticals.

Handling chlorosulfonic acid requires extreme caution due to its corrosive nature and the hazardous fumes it emits, primarily hydrogen chloride and sulfur oxides. It can cause severe burns on contact with skin, eyes, and respiratory tissues. Appropriate personal protective equipment, such as gloves, eye protection, and respiratory protection, is essential when working with this compound. Storage should be in tightly sealed containers in a cool, dry, and well-ventilated area, away from water and incompatible materials.