Na-NaOH-Fe(OH)2-Fe(OH)3-Fe2O3-Fe2(SO4)3-BaSO4

 Na→NaOH→Fe(OH)₂→Fe(OH)₃→Fe₂O₃→Fe₂(SO₄)₃→BaSO₄2Na +2H₂O =2NaOH +H₂↑2NaOH + FeCI₂= Fe(OH)₂↓ +2NaCI4Fe(OH)₂+O₂+2H₂O= 4Fe(OH)₃↓2Fe(OH)₃ + t= Fe₂O₃ + 3H₂OFe₂O₃ + 3H₂SO₄= Fe₂(SO₄)₃ + 3H₂OFe₂(SO₄)₃ + 3BaCI₂ = 3BaSO₄↓ + 2FeCI₃