Sodium sulfite

 

Sodium sulfite

Chemical formula	Na2SO3
OTP appearance	white solid
Molar Mass(g/mol)	126.043
Density(g/cc)	2.633(anh)
Melting Point(°C)	500
Boiling Point(°C)	decomp
Solubility in water(g/L)	270
NFPA 704	0 1 0

Uses

Justification Questioned

Other

• Feedstock for sodium bisulfate, sodium thiosulfate and calcium sulfite
• A solid form of "storage" for sulfur dioxide

Natural occurrence

• Does not occur naturally

Production

Synthesis

via sulfur dioxide

Bubble sulfur dioxide through a saturated solution of sodium hydroxide, producing sodium sulfite

2 NaOH + SO₂ → Na₂SO₃ + H₂O

via sodium bisulfite 1

Combine sodium bisulfite with a stochiometric amount of additional sodium carbonate

2 NaHSO₃(aq) + Na₂CO₃(aq) → 2 Na₂SO₃(aq) + H₂O(l) + CO₂(g)

via sodium bisulfite 2

Combine sodium bisulfite with calcium hydroxide, producing calcium sulfite and sodium sulfite along with water

2 NaHSO₃ + Ca(OH)₂ → CaSO₃ + Na₂SO₃ + H₂O

See Also

• sodium bisulfite
• sodium thiosulfate
• sodium sulfate
• sodium bisulfate