a) 2K⁺¹Mn⁺⁷O4⁻² + 5H2⁺¹O2⁻¹ + 3H2⁺¹S⁺⁶O4⁻² ---> K2⁺¹SO4 + 2Mn⁺²S⁺⁶O4⁻² + 8H2⁺¹O⁻² + 5O2⁰
Mn⁺⁷ +5e⁻---> Mn⁺² se reduce (agent ox) ||2
O2⁻¹ -2e⁻--> O2⁰ se oxideaza (agent red.) ||5
b) 2Cu⁺²Cl2⁻¹ + 4K⁺¹I⁻¹ --> 2Cu⁺²I⁻² + 4K⁺¹Cl⁻¹ + I2⁰
I⁻¹ +1e⁻--> I⁻² ||2 se reduce (ag. ox)
2I⁻¹ -2e⁻--> I2⁰ ||1 se oxideaza (ag red)
c) 2Mn⁺⁴O2⁻² + 2H2⁺¹S⁺⁶O4⁻² --> 2Mn⁺²S⁺⁶O4⁻² + O2⁰ + 2H2⁺¹O⁻²
Mn⁺⁴ +2e⁻--> Mn⁺² se reduce (ag.ox) ||4||2
O2⁻² -4e⁻--> O2⁰ se oxideaza (ag.red) ||2||1