Sodium sulfite

Description

Sodium sulfite (sodium sulphite) is a soluble compound of sodium. It is a product of SO2 scrubbing, a part of the flue gas desulfurization process. It is also used as a preservative to prevent dried fruit from discoloring, and for preserving meats, and is used in the same way as sodium thiosulfate to convert elemental halides to their respective acids, in photography and for reducing chlorine levels in pools.

Chemical Properties

Sodium sulfite is decomposed by even weak acids, giving up sulfur dioxide gas.

Na2SO3 + 2 H+ → 2 Na+ + H2O + SO2

A saturated aqueous solution has pH of ~9. Solutions exposed to air are eventually oxidized to sodium sulfate.

The Uses of Sodium sulfite

sodium sulfite has anti-septic, preservative, and anti-oxidant properties. Sodium sulfite is also a topical anti-fungal.

Health hazards

Exposure to sodium sulfite, especially powder, can cause irritation to the skin, eyes, and respiratory tract. If inhaled, sulfites may cause sensitization (develop an allergic reaction). Breathing sulfite dusts may aggravate asthma or other pulmonary (breathing) diseases and may cause headaches, breathing difficulties, or heart irregularity. Ingestion may cause gastrointestinal irritation, nausea, vomiting and diarrhea. Overexposure may result in death.