Răspuns:
1) 3 I2 + 10 HNO3 → 6 HIO3 + 10 NO + 2 H2O
6 I0 - 30 e- → 6 IV (oxidare) agent reducator
10 NV + 30 e- → 10 NII (reducere) agent oxidant
I2 agent reducator
HNO3 agent oxidant
2) 3 V2O5 + 10 Al → 6 V + 5 Al2O3
6 VV + 30 e- → 6 V0 (reducere) agent oxidant
10 Al0 - 30 e- → 10 AlIII (oxidare) agent reducator
V2O5 agent oxidant
Al agent reducator
3) S + 2 HNO3 → H2SO4 + 2 NO
S0 - 6 e- → SVI (oxidare) agent reducator
2 NV + 6 e- → 2 NII (reducere) agen oxidant
S agent reducator
HNO3 agent oxidant
4)
I2 + 5 Cl2 + 6 H2O → 2 HIO3 + 10 HCl
2 I0 - 10 e- → 2 IV (oxidare) agent reducator
10 Cl0 + 10 e- → 10 Cl-I (reducere) agent oxidant
I2 agent reducator
Cl2 agent oxidant
Explicație: