Redox Reaction Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Redox Reaction.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A chemical reaction in which electrons are transferred from one substance (the reducing agent, which is oxidized) to another (the oxidizing agent, which is reduced).

One thing loses electrons (oxidized), another gains them (reduced).

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Redox reactions always have both oxidation and reduction happening simultaneously.

Common stuck point: The substance that gets oxidized is the 'reducing agent' (it reduces the other).

Sense of Study hint: When analyzing a redox reaction, identify what is oxidized and what is reduced. First assign oxidation numbers to every atom before and after the reaction. Then find which element increased in oxidation number (oxidized, the reducing agent) and which decreased (reduced, the oxidizing agent). Finally, verify that total electrons lost equals total electrons gained.

Worked Examples

Example 1

easy
Define a redox reaction and explain the relationship between oxidation and reduction.

Solution

  1. 1
    A redox (reduction-oxidation) reaction involves the transfer of electrons between species.
  2. 2
    Oxidation is the loss of electrons (increase in oxidation number). Reduction is the gain of electrons (decrease in oxidation number).
  3. 3
    Oxidation and reduction always occur together — one species cannot lose electrons unless another gains them. Remember: OIL RIG (Oxidation Is Loss, Reduction Is Gain).

Answer

\text{Redox: electron transfer. Oxidation = loss, Reduction = gain.}
Redox reactions are one of the most important classes of chemical reactions. They include combustion, corrosion, photosynthesis, respiration, and all electrochemical processes (batteries, electrolysis).

Example 2

medium
In the reaction \text{Zn(s)} + \text{CuSO}_4\text{(aq)} \rightarrow \text{ZnSO}_4\text{(aq)} + \text{Cu(s)}, identify the oxidizing agent and the reducing agent.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

medium
Determine whether the following reaction is a redox reaction: \text{HCl(aq)} + \text{NaOH(aq)} \rightarrow \text{NaCl(aq)} + \text{H}_2\text{O(l)}. Justify your answer.

Example 2

hard
Balance the following redox reaction in acidic solution using the half-reaction method: \text{MnO}_4^- + \text{Fe}^{2+} \rightarrow \text{Mn}^{2+} + \text{Fe}^{3+}.
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Background Knowledge

These ideas may be useful before you work through the harder examples.

oxidationreduction