Balancing Equations by the Ion-Electron Method

1. Write the equation to be balanced.
2. Identify what was oxidized and what was reduced.

OXIDATION
REDUCTION
Charge goes up
Charge goes down
Losses electrons
Gains electrons
Gains oxygen
Losses oxygen
Losses hydrogen
Gains hydrogen

3. Write an equation for the oxidized substance and an equation for the reduced substance.
4. Add H+’s, OH-‘s and/or H2O’s to either side of each half-reaction to balance the number of atoms of each type. AFTER, you add H+’s, OH-‘s and/or H2O’s, make sure the equation is balanced.

Atoms to be Balanced
ACIDIC (H+)
BASIC (OH-)
Oxygen
1. Add one H2O for each oxygen, to the side lacking oxygen
2. Add two H+ for each H2O, to the other side for balance
1. Add two OH- for each oxygen (to the side lacking oxygen)
2. Add one H2O to the other side for every two OH-
Hydrogen
1. Add H+
1. Add one H20 to the side needing H+
2. Add one (or more) OH- to the other side for balance.

5. For each half-reaction, add up the total charges on each side and equalize them by adding or subtracting electrons from the left side of the half reaction.
6. Find a least common multiple for the gain or loss of electrons in the two half-reactions and equalize the gain with the loss.
7. Add the two half reactions, canceling the gained and lost electrons (and any extra H2O or H+), and the equations. The equation should be balanced, make a chart to check.