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Sodium metabisulfite is a white or yellow crystalline powder or small crystal with a strong SO2 odor, a specific gravity of 1.4, soluble in water, and the aqueous solution is acidic. When it is in contact with a strong acid, it releases SO2 to form a corresponding salt. When it is left in the air, it oxidizes. It is Na2S2O6, so the product cannot be stored for a long time. Above 150 degrees Celsius, SO2 is decomposed.

Product specifications:

Sulfur dioxide ≥ 65%

Iron ≤ 0.005%

Water insoluble matter ≤ 0.05%

PH value: 4.0-4.6

English name: sodium metabisulfite

Category: Antioxidants.

Physicochemical properties

Appearance and Properties: It is a colorless prismatic crystal or white powder; it has sulfur dioxide taste, acidity and saltiness;

Solubility: Soluble in water, the aqueous solution is acidic (54 g / 100 ml water at 20 ° C; 81.7 g / 100 ml water at 100 ° C). Soluble in glycerin, slightly soluble in ethanol. The relative density is 1.4. Soluble in water, soluble in glycerin, slightly soluble in ethanol. It is easily decomposed by moisture and easily oxidized to sodium sulfate in exposed air. Contact with strong acid releases sulfur dioxide to form the corresponding salt. Heat to 150 ° C decomposition.

Stability and reactivity

Incompatible materials: strong acid, strong oxidant.

Conditions to avoid: humid air.