Цепь
1)FeCl2 -> Cl2 -> FeCl3 -> Fe(OH)3 -> Fe2O3 -> Fe -> Fe3O4
2) Cl2 -> HClO3
3) FeCl3 -> Zn -> Na2ZnO2

1/FeCl₂ = Fe + Cl₂2Fe + 3Cl₂ = 2FeCl₃FeCl₃ + 3KOH = Fe(OH)₃ + 3KCl2Fe(OH)₃ = Fe₂O₃ + 3H₂OFe₂O₃ + 3C = 2Fe + 3CO3Fe + 2O₂ = Fe₃O₄2\Cl₂ + H₂O = HClO + HCl 3HClO = HClO₃ + 2HCl3\FeCl₃ + 3Zn = Fe + 3ZnCl₂ZnCl₂ = Zn + Cl₂Zn + 2NaOH = Na₂ZnO₂ + H₂