Question

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

Answer 1

1/
FeCl₂ = Fe + Cl₂
2Fe + 3Cl₂ = 2FeCl₃
FeCl₃ + 3KOH = Fe(OH)₃ + 3KCl
2Fe(OH)₃ = Fe₂O₃ + 3H₂O
Fe₂O₃ + 3C = 2Fe + 3CO
3Fe + 2O₂ = Fe₃O₄
2
Cl₂ + H₂O = HClO + HCl 
3HClO = HClO₃ + 2HCl
3
FeCl₃ + 3Zn = Fe + 3ZnCl₂
ZnCl₂ = Zn + Cl₂
Zn + 2NaOH = Na₂ZnO₂ + H₂