College Chemistry : Balancing Redox Reactions

Study concepts, example questions & explanations for College Chemistry

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Example Questions

Example Question #1 : Balancing Redox Reactions

Balance the following redox reaction in acidic conditions:

Possible Answers:

Correct answer:


Start by writing the half reactions for the equation

All atoms except for O and H are already balanced, so we can go straight to balancing O and H atoms. First balance O atoms by adding H2O

Now balance H atoms with H+

Balance each half reaction's electrical charge with electrons

Now combine both half reactions to get the overall reaction. Be sure to cancel out electrons by multiplying the oxidation reaction by 5 and the reduction reaction by 2. This will give 10 e- on each side of the overall reaction so that they cancel out.

Overall Reaction:


Notice that we have  H2O and H+ on both sides of the equation, so we need to simplify. Subtract the 5 H2O on the reactant side from the 8 H2O on the product side which leaves 3 H2O on the reactant side. Then subtract the 10 H+ on the product side from the 16 H+ on the reactant side which leave 6 H+ on the reactant side. Now we have the simplified overall reaction

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