Fe-(над стрелкой HCl)A-(NaOH)Б-(t)В-(HCl)Г
Fe + 2HCl = FeCl2 + H2
FeCl2 + 2NaOH = Fe(OH)2 + 2NaCl
Fe(OH)2 = FeO + H2O
FeO + 2HCl = FeCl2 + H2O