How Is Sodium Metabisulfite Produced?

Sodium metabisulfite is typically produced by the reaction of sodium bisulfite with an oxidizing agent such as hydrogen peroxide or sodium hypochlorite. The reaction occurs in aqueous solution at a controlled pH and temperature, and produces sodium metabisulfite as a white crystalline solid.

The overall reaction can be represented as follows:

2 NaHSO3 + H2O2 → Na2S2O5 + 2 H2O

Alternatively, sodium metabisulfite can also be produced by heating sodium sulfite with sulfur dioxide gas:

Na2SO3 + 2 SO2 → Na2S2O5

This process requires careful control of temperature and pressure to produce high-quality sodium metabisulfite crystals. After production, the compound may undergo additional processing steps such as purification or drying to remove impurities and ensure product quality.