Oxidation Number Method
A technique for balancing redox equations by equating the total increase and decrease in oxidation numbers.
Formula / equation
Σ increase = Σ decrease
Unit
Dimensionless
In depth
Oxidation numbers are assigned to every atom, the species that change are identified, and coefficients are chosen so that electrons lost equal electrons gained. Remaining atoms are then balanced by inspection, with H⁺ or OH⁻ and water added last to complete hydrogen and oxygen.
Examples in the real world
Balancing Cu + HNO₃ → Cu(NO₃)₂ + NO + H₂O by matching copper's +2 rise against nitrogen's 3-unit fall.