1) 12HCl + 2CrO3 = 2CrCl3 + 3Cl2 + 6H2O:
2Cl- -2e- = Cl2 | 2 | 6 | 3 |
Cr+6 +3e- = Cr3+ | 2 | | 2 |;
2) 10Fe + 4KOH + 6KNO3 = 10KFeO2 + 3N2 + 2H2O:
Fe -3e- = Fe+3 | 3 | 30 | 10 |
2N+5 +10e- = N2 | 10 | | 3 |;
3) H2S + H2SO4 (конц.) = SO2 + 2H2O + S:
S-2 -2e- = S | 2 | 2 | 1 |
S+6 +2e- = S+4 | 2 | | 1 |;
4) 2Mn2(SO4)3 = 4MnSO4 + O2 + 2SO3:
2Mn+3 +2e- = 2Mn+2 | 2 | 4 | 2 |
2(O)-2 -4e- = O2 | 4 | | 1 |;
5) PbS + 4H2O2 = PbSO4 + 4H2O:
S-2 -8e- = S+6 | 8 | 8 | 1 |
(O2)-2 +2e- = 2(O)-2 | 2 | | 4 |;
6) KClO3 + 6KOH + 3MnO2 = 3K2MnO4 + 3H2O + KCl:
Cl+5 +6e- = Cl- | 6 | 6 | 1 |
Mn+4 -2e- = Mn+6 | 2 | | 3 |.