Balancing Redox Reactions and Identifying Redox Agents

What are Redox Reactions?

Redox reactions involve the transfer of electrons between substances. They consist of two half-reactions: oxidation and reduction.

• Oxidation: Loss of electrons, leading to an increase in oxidation number.
• Reduction: Gain of electrons, leading to a decrease in oxidation number.

Oxidizing and Reducing Agents

In a redox reaction, the substance that gets reduced is the oxidizing agent, and the one that gets oxidized is the reducing agent.

• Oxidizing Agent: Gains electrons and is reduced.
• Reducing Agent: Loses electrons and is oxidized.

Identifying Oxidizing and Reducing Agents

To identify these agents, look at the change in oxidation numbers:

• If the oxidation number increases, the substance is oxidized (reducing agent).
• If the oxidation number decreases, the substance is reduced (oxidizing agent).

Balancing Redox Reactions Using Oxidation Numbers

Follow these steps to balance redox reactions:

1. Assign Oxidation Numbers: Determine the oxidation number of each element in the reaction.
2. Identify Changes: Note which elements change oxidation numbers.
3. Balance Electron Transfer: Ensure the number of electrons lost equals the number of electrons gained.
4. Balance Remaining Atoms: Adjust coefficients to balance the rest of the atoms.
5. Check Charges: Ensure that the charges are balanced on both sides of the equation.

Example: Balancing Redox Reaction

Balance the reaction: $$\text{MnO}_4^- + \text{Fe}^{2+} \rightarrow \text{Mn}^{2+} + \text{Fe}^{3+}$$