page_title: Sodium bisulfite
section_title: Reactivity and uses
hierarchical_section_title: Sodium bisulfite / Reactivity and uses
caption_attribution_description: A tank containing 25% sodium bisulfite at the Sunnyvale Water Pollution Control Plant.
context_page_description: Sodium bisulfite is a chemical mixture with the approximate chemical formula NaHSO₃. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. It is a white solid with an odour of sulfur dioxide. Regardless of its ill-defined nature, "sodium bisulfite" is a food additive with E number E222.
context_section_description: Sodium bisulfite is a common industrial reducing agent, as it readily reacts with dissolved oxygen:
  2 NaHSO₃ + O₂ → 2 NaHSO₄
  It is usually added to large piping systems to prevent oxidative corrosion. In biochemical engineering applications, it is helpful to maintain anaerobic conditions within a reactor.
  It is used for preserving food and beverages.
caption: A tank containing 25% sodium bisulfite at a water treatment plant in Sunnyvale, California.
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