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How to Balance Redox Reactions - Balancing Redox Reactions

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Balancing Redox Reactions - Half-Reaction Method
This is a diagram that describes the half-reactions of a redox reaction.

This is a diagram that describes the half-reactions of a redox reaction or oxidation-reduction reaction.

Cameron Garnham, Creative Commons License
To balance redox reactions, assign oxidation numbers to the reactants and products to determine how many moles of each species are needed to conserve mass and charge. First, separate the equation into two half-reactions, the oxidation portion and the reduction portion. This is called the half-reaction method of balancing redox reactions or the ion-electron method. Each half-reaction is balanced separately and then the equations are added together to give a balanced overall reaction. We want the net charge and number of ions to be equal on both sides of the final balanced equation.

For this example, let's consider a redox reaction between KMnO4and HI in an acidic solution:

MnO4- + I- → I2 + Mn2+

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