А) S + 3KBrO + H2O = H2SO4 + 3KBr, баланс:
S -6e- + 4H2O = (SO4)2- + 8H+ | 6 | 6 | 1 |
(BrO)- +2e- + 2H+ = Br- + H2O | 2 | | 3 |;
S + 3(BrO)- + H2O = (SO4)2- + 3Br- + 2H+;
б) Cl2 + Zn + 4NaOH = Na2[Zn(OH)4] + 2NaCl, баланс:
Cl2 +2e- = 2Cl- | 2 | 2 | 1 |
Zn -2e- + 4OH- = [Zn(OH)4]2- | 2 | | 1 |;
Cl2 + Zn + 4OH- = 2Cl- + [Zn(OH)4]2-;
в) 2Cl2 + Sn + 6NaOH = Na2[Sn(OH)6] + 4NaCl, баланс:
Cl2 +2e- = 2Cl- | 2 | 4 | 2 |
Sn -4e- + 6OH- = [Sn(OH)6]2- | 2 | | 1 |;
2Cl2 + Sn + 6OH- = 4Cl- + [Sn(OH)6]2-.