Steps to balancing a redox reaction

  1. The Oxidation Number Method
    1. Determine the oxidation numbers for all elements in the reactants and the products.
    2. Identify which species is being oxidized and which species is being reduced.
    3. Determine how many electrons are lost by each atom of the oxidized species.
    4. Determine how many electrons are gained by each atom of the reduced species.
    5. Balance the number of electrons gained and lost.
    6. Balance the reaction is balanced for elements. Add H2O and H1+ (aq) as necessary.
    7. Check that the reaction is balanced for charge.

  2. The Half Reaction Method
    1. Identify which compound is oxidized.
      1. Write the oxidation half reaction.
      2. Balance the half reaction for elements.
      3. Add H2O and H1+ (aq) as necessary.
      4. Balance the half reaction for charge by adding electrons as products.
    2. Identify which compound is reduced
      1. Write the reduction half reaction
      2. Balance the half reaction for elements.
      3. Add H2O and H1+ (aq) as necessary.
      4. Balance the half reaction for charge by adding electrons as reactants.
    3. Balance the number of electrons from the oxidation and the reduction.
    4. Add the two reactions together.
    5. Check that the reaction is balanced for elements.
    6. Check that the reaction is balanced for charge.

  3. If the reaction is in a basic solution.
    1. Change all the H1+ (aq) to H2O.
    2. Change all the H2O to OH1- (aq)

  4. Check that the reaction is balanced for elements.
  5. Check that the reaction is balanced for charge.


This page is maintained by
Scott Van Bramer
Department of Chemistry
Widener University
Chester, PA 19013

Please send any comments, corrections, or suggestions to svanbram@science.widener.edu.

This page has been accessed 76 times since 4/12/97.
Last Updated 4/12/97