سدیم سولفیت
| Formula | Na2O3S |
| Chemical formula | Na2SO3 |
| Density | 2.63 g/cm3 (20°C) |
| Molar mass | 126.04 g/mol |
| Bulk density | ~ 1480 kg/m3 |
| CAS number | 7757-83-7 |
| HS Code | 28321000 |
| EC number | 231-821-4 |
| Storage | Without limitation |
| SDS | available |
| Odour | oderless |
| Form | powder |
| Color | white |
| p H | 8.8 – 1.0(50g/l 20 °C) |
| Solubility in water | 220g/l (20°C) |
| Solubility in ethanol | almost insoluble |
| Boiling point | decomposition |
| Melting point | >500 °C |
| Thermal decomposition | >500 °C |
| Assay | 95.0 – 100.5 | % | |
| Description | Conforms | ||
| Identification | Conforms | ||
| Color & clarity of solution | Conforms | ||
| Heavy metals | ≤ | 10 | ppm |
| Limit of iron | ≤ | 10 | ppm |
| Limit of selenium | ≤ | 10 | ppm |
| Limit of thiosulfates | ≤ | 0/1 | % |
| Limit of zinc | ≤ | 25 | ppm |
| SO2 | ≤ | 48 | % |
Sodium sulfite is a white, crystalline inorganic compound used mainly as an antioxidant, preservative, and reducing agent in various industrial and laboratory applications.
🏭⚗️ Production
Sodium sulfite is typically produced by bubbling sulfur dioxide gas (SO₂) into a sodium hydroxide (NaOH) or sodium carbonate (Na₂CO₃) solution, resulting in formation of sodium sulfite. The resulting solution is then concentrated and crystallized to obtain pure solid Na₂SO₃.
🔬 Properties
The chemical formula is Na₂SO₃ with a molar mass of approximately 126.04 g/mol. It appears as a white, odorless, crystalline powder that is soluble in water but insoluble in alcohol. Aqueous solutions are mildly alkaline and have reducing properties. It is sensitive to air and moisture, gradually oxidizing to sodium sulfate over time.
🧪 Applications
Sodium sulfite is used as an oxygen scavenger in boiler water systems to prevent corrosion, as a preservative in dried fruits and wines to inhibit microbial growth and browning, and as a bleaching agent in the pulp and textile industries. It also plays a role in developing photographic films and in laboratory settings for redox reactions.
⚠️ Safety
Sodium sulfite is generally safe in controlled use, but it may cause allergic reactions or asthma symptoms in sensitive individuals when inhaled or ingested in food. It can irritate the eyes, skin, and respiratory tract. Appropriate protective gear like gloves and masks should be used during handling, and it should be stored in a cool, dry place away from acids and oxidizing agents.





