Reduction Chemistry Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
In the reaction 2Mg+O2→2MgO2\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO}, identify which species is reduced.

Solution

  1. 1
    Oxygen goes from oxidation state 00 (in O2\text{O}_2) to −2-2 (in MgO).
  2. 2
    A decrease in oxidation number means the species has gained electrons.
  3. 3
    Therefore, O2\text{O}_2 is reduced: O2+4e−→2O2−\text{O}_2 + 4e^- \rightarrow 2\text{O}^{2-}.

Answer

O2 is reduced (0 → -2)\text{O}_2\text{ is reduced (0 → -2)}
Reduction is the gain of electrons (RIG in OIL RIG). The substance that is reduced is the oxidizing agent because it takes electrons from the other reactant.

About Reduction

The gain of electrons by an atom, ion, or molecule during a chemical reaction, resulting in a decrease in its oxidation state.

Learn more about Reduction →

More Reduction Examples

Example 2 medium

In a blast furnace, iron ore is reduced: [formula]. Identify the reducing agent.

Example 3 easy

In the reaction [formula], is copper being oxidized or reduced?

Example 4 medium

In the reaction [formula], which substance is reduced?

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