Balancing Redox Equations Using the Ion-Electron Method

The following steps may be used to balance oxidation—reduction (redox) equations by the ion-electron (half-reaction) method. While other methods may be successful, none is as consistently successful as is this particular method. The half-reactions used in this process will also be necessary when considering other electrochemical phenomena, thus the usefulness of half-reactions goes beyond balancing redox equations. 

The basic idea of this method is to split a complicated equation into two parts called half-reactions. These simpler parts are then balanced separately, and recombined to produce a balanced overall equation. The splitting is done so that one of the half-reactions deals only with the oxidation portion of the redox process, whereas the other deals only with the reduction portion. What ties the two halves together is the fact that the total electrons lost by the oxidation process MUST equal the total gained by the reduction process (step 6). 

It is very important that you follow each of the steps listed below completely, in order do not try to take any short cuts. There are many modifications of this method. For example, a modification allows you to balance all the reactions as if they were in acidic solution followed by a step, when necessary, to convert to a basic solution. Switching to a modification before you completely understand this method very often leads to confusion, and an incorrect result. 

Assign Oxidation Numbers and Begin the Half-Reactions, One for Oxidation and One for Reduction 

Beginning with the following example (phases are omitted for simplicity)  

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Balancing Redox Equations Using the Ion-Electron Method... 

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