natriumsulfitt

Natriumsulfitt, or sodium sulfite, is an inorganic salt with the chemical formula Na2SO3. It is the sodium salt of sulfite and appears as a white, water-soluble solid. In solution it acts as a mild reducing agent and can affect oxidation-reduction processes in various applications.

Production and properties

Sodium sulfite is typically produced by absorbing sulfur dioxide in an aqueous sodium hydroxide solution: SO2 + 2 NaOH → Na2SO3 + 2 H2O. In air, sulfite can be slowly oxidized to sulfate (Na2SO4). In acidic conditions, sulfite converts to sulfurous acid (H2SO3), which readily decomposes to sulfur dioxide (SO2). The compound is highly soluble in water and forms alkaline solutions.

Applications

Natriumsulfitt is used as a reducing agent in chemical synthesis and as a preservative and antioxidant in the food and beverage industry. In the wine, fruit juice, and dried fruit sectors, it helps prevent oxidation and browning. It also finds use in the paper, textile, and photographic industries for bleaching, stabilization, and preservation of dyes and solutions.

Safety and regulation

Sodium sulfite solutions can irritate the skin, eyes, and respiratory tract. Some individuals are sulfite-sensitive and may experience adverse reactions, including asthma-like symptoms. When acidified, it releases sulfur dioxide, a toxic gas. In many regions, products containing sulfites are subject to labeling and usage restrictions to protect sensitive individuals and consumers.

Related compounds

Related sulfite and bisulfite systems include sodium bisulfite (NaHSO3) and sodium metabisulfite (Na2S2O5), which have related chemistry and applications in preservation and oxidation control.