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