Balancing Redox Equations: tips
1. Use the net ionic equation when possible.
2. Make sure you get the oxidation states right!
3. Make sure you get the charges right on polyatomic ions! Double check when possible.
4. Avoid having the same compounds in both half-reactions.
For example: PCl3  PH3 + Cl2. Do NOT have PCl3 in both half reactions…instead see suggestion 5.
5. Balance elements with ions if you can’t figure out how to balance.
For example: PCl3  PH3 -- Balance chlorines with Cl-.
6. It’s ALWAYS ok to add H2O or H+.