Half Reactions | Explore Redox Processes Now

Redox Half Reactions

Core Concept

A redox reaction can be split into two half-reactions: one for oxidation and one for reduction.

Oxidation Half-Reaction: Shows the loss of electrons (LEO: Loss of Electrons is Oxidation).
Reduction Half-Reaction: Shows the gain of electrons (GER: Gain of Electrons is Reduction).

Key Tips

Redox half-reactions break a redox reaction into oxidation and reduction components.
Electrons lost in oxidation must equal electrons gained in reduction.
Use systematic steps to balance redox reactions in acidic or basic solutions.
Mastering half-reactions is essential for understanding electrochemical cells and redox processes.

Test Yourself

Assorted Multiple Choice

Consider the following unbalanced chemical reaction:$$\text{Mg}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Mg}^{2+}(aq) + \text{Cu}(s)$$Which equation correctly represents the reduction half-reaction occurring in this process?

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Writing Separate Oxidation and Reduction Half-Reactions

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Key Terms

Oxidation:

Occurs when a species loses electrons.
The oxidation state increases.
Example: Zn (s)→Zn2+(aq)+2e−\text{Zn (s)} \rightarrow \text{Zn}^{2+} (aq) + 2e^-Zn (s)→Zn2+(aq)+2e−

Reduction:

Occurs when a species gains electrons.
The oxidation state decreases.
Example: Cu2+(aq)+2e−→Cu (s)\text{Cu}^{2+} (aq) + 2e^- \rightarrow \text{Cu (s)}Cu2+(aq)+2e−→Cu (s)

Electrons:

Electrons lost in oxidation must equal electrons gained in reduction.

Steps to Write Redox Half-Reactions

Identify the Redox Reaction:
- Determine which species is oxidized and which is reduced.
Write the Oxidation Half-Reaction:
- Show the species losing electrons and balance for mass and charge.
Write the Reduction Half-Reaction:
- Show the species gaining electrons and balance for mass and charge.
Balance the Electrons:
- Ensure the number of electrons lost in oxidation equals the number gained in reduction.
Combine the Half-Reactions:
- Add the half-reactions to get the overall balanced redox reaction.

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