natriumsulfit

Natriumsulfit, also known as sodium sulfite, is an inorganic salt with the chemical formula Na2SO3. It appears as a white, odorless, crystalline solid that is highly soluble in water. In aqueous solution, sulfite ions (SO3^2−) can act as reducing agents, and the compound can react with acids to release sulfur dioxide.

Production and chemistry: Sodium sulfite is produced industrially by absorbing sulfur dioxide into an aqueous alkaline solution, such as sodium hydroxide, to form Na2SO3 (for example SO2 + 2 NaOH → Na2SO3 + H2O). In solution, the sulfite species exist in equilibrium with bisulfite (HSO3^−) depending on pH. It can also be formed by reduction of sodium sulfate under suitable conditions, but absorption of SO2 into alkaline media is the common method.

Applications: Sodium sulfite is widely used as a reducing agent and antioxidant. In the food industry it serves as a preservative and anti-oxidant to limit browning and spoilage in dried fruits, wines, and other products. In the paper and pulp industry it is used for bleaching and in the textile industry for various chemical processes. It is also employed in photography, water treatment, and certain chemical syntheses as a milder alternative to more aggressive reducing agents.

Safety and handling: Sodium sulfite can irritate the skin, eyes, and respiratory tract, and sensitive individuals may experience allergic reactions or asthma-like symptoms. It reacts with acids to release sulfur dioxide, a toxic gas, so containers must be kept tightly closed and away from acids. It should be stored in a cool, dry place away from oxidizing agents and moisture; proper eye and skin protection is recommended when handling.