CaO + SO₂ = CaSO₃
CaCl₂ + Li₂SO₃ = CaSO₃ + 2LiCl
Ca(OH)₂ + SO₂ = CaSO₃ + H₂O
CaCl₂ + K₂SO₃ = CaSO₃ + 2KCl
CaCl₂ +Na₂SO₃ = CaSO₃ + 2NaCl
Ca(NO₃)₂ + K₂SO₃ = CaSO₃ + 2KNO₃
CaI₂ + Na₂SO₃ = CaSO₃ + 2NaI
CaBr₂ + K₂SO₃ = CaSO₃ + 2KBr
CaI₂ + (NH₄)₂SO₃ = CaSO₃ + 2NH₄I
CaBr₂ + Na₂SO₃ = CaSO₃ + 2NaBr