1.
MnO2+ 4HCl -> MnCl2+ Cl2+ 2H2O
Cl2+ H2 $\buildrel{{as}}\over\longrightarrow$ 2HCl
NaOH+ HCl -> NaCl+ H2O
2NaCl $\buildrel{{đpnc}}\over\longrightarrow$ 2Na+ Cl2
4Cl2+ H2S+ 4H2O -> 8HCl+ H2SO4
NaCl+ H2SO4 -> NaHSO4+ HCl
2.
2KMnO4+ 16HCl -> 2KCl+ 2MnCl2+ 5Cl2+ 8H2O
3Cl2+ 6KOH -> 5KCl+ KClO3+ 3H2O
KClO3+ 6HCl -> KCl+ 3Cl2+ 3H2O
Fe+ 3/2Cl2 $\buildrel{{t^o}}\over\longrightarrow$ FeCl3
FeCl3+ 3KOH -> Fe(OH)3+ 3KCl
2KCl+ 2H2O $\buildrel{{đpmn}}\over\longrightarrow$ 2KOH+ H2+ Cl2
3.
BaCl2 $\buildrel{{đpnc}}\over\longrightarrow$ Ba+ Cl2
Cl2+ H2 $\buildrel{{as}}\over\longrightarrow$ 2HCl
Fe+ 2HCl -> FeCl2+ H2
2FeCl2+ 3Cl2 -> 2FeCl3
3Ba(OH)2+ 2FeCl3 -> 3BaCl2+ 2Fe(OH)3
BaCl2+ H2SO4 -> BaSO4+ 2HCl