1) 3K2MnO4+2H2O=
=2KMnO4+MnO2+4KOH
Mn{6+} - e = Mn{7+}. |2
Mn{6+} + 2e = Mn{4+}. |1
2) 3HClO3=HClO4+2ClO2+H2O
Cl{5+} - 2e = Cl{7+}|1
Cl{5+} + e = Cl{4+} |2
3) 3HNO2=HNO3+2NO+H2O
N{3+} - 2e = N{5+}. |1
N{3+} + e = N{2+}. |2
