Redox Reaction

Redox reactions are reactions that involve either a transfer of electrons or a change in the oxidation numbers of the substances that are taking part in the reaction.

The substance gaining oxygen is oxidized, while the substance losing oxygen is reduced.

Losing electrons refers to oxidation. Gaining electrons refers to reduction.

Reducing agent: substance that loses electrons
Oxidizing agent: substance that accepts electrons

How to balance Redox Equations: (two methods)

Using Oxidation-Number Changes

Step 1: Assign the oxidation numbers to all of the atoms in an equation
Step 2: Identify which atoms are oxidized and which atoms are reduced.
Step 3: Use one bracketing line to connect the atoms that undergo
oxidation and another bracketing line to connect those that undergo reduction.
Step 4: Make the total increase in oxidation number equal to the total decrease in oxidation number by using the correct coefficients.
Step 5: Balance the equation for both atoms and charge.

Using Half Reactions

Step 1: Write the unbalanced equation in ionic form
Step 2: Separate oxidation and reduction processes in half-reactions
Step 3: Balance the atoms in the half-reaction
Step 4: Add enough electrons to one side of each half-reaction to balance the charges

The electrons will be added to opposite sides of the half-reaction

Step 5: Multiply each half-reaction by an appropriate number that will make the number of electrons equal in both
Step 6: Add the half-reactions to show an overall equation

Step 7: Add the spectator ions and balance the equation

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