HOSO3

HOSO3, also known as hydrogensulfite or bisulfite, is a chemical species with the formula HO2SO2-. It is an anion derived from sulfurous acid, H2SO3. In aqueous solutions, it exists in equilibrium with sulfite ions (SO32-) and sulfurous acid. The equilibrium is pH dependent, with hydrogensulfite being more prevalent in acidic to neutral conditions and sulfite dominating in alkaline conditions.

Hydrogensulfite is a significant reducing agent. It plays a role in various chemical processes, including in some industrial applications like water treatment and as a bleaching agent. It is also encountered in biological systems, though its presence and function are complex and can vary depending on the organism. In the context of environmental chemistry, hydrogensulfite can be involved in atmospheric reactions and acid rain formation. It is important to note that the term bisulfite is often used interchangeably with hydrogensulfite in chemical literature and industry.