Bài 1:
MnO2+ 4HCl -> MnCl2+ Cl2+ 2H2O
2Na+ Cl2 $\buildrel{{t^o}}\over\longrightarrow$ 2NaCl
2NaCl+ 2H2O $\buildrel{{đpmn}}\over\longrightarrow$ 2NaOH+ H2+ Cl2
FeCl3+ 3NaOH -> Fe(OH)3+ 3NaCl
2Fe(OH)3 $\buildrel{{t^o}}\over\longrightarrow$ Fe2O3+ 3H2O
Fe2O3+ 6HCl -> 2FeCl3+ 3H2O