# Reduction

A reaction where a substance loses oxygen or gains electrons.

Chemistry (school) · Part 07: Metals and electrolysis · Card 4 of 9 · Last updated 2026-10-19

## Analogy

The opposite of oxidation. Gaining electrons is reduction, like taking on a coat.

## Example

**Remember RIG**

Reduction Is Gain of electrons
Cu2+ + 2e- -> Cu

## In practice

Iron oxide is reduced to iron when it is heated with carbon in a blast furnace.

## Practice

### Flashcards

- **What is reduction in terms of electrons?** Gain of electrons.

### Interview questions

**Describe what happens at each electrode in the electrolysis of molten lead bromide.**

- Lead ions move to the cathode and gain electrons
- Lead metal forms at the cathode
- Bromide ions move to the anode and lose electrons
- Bromine gas forms at the anode

## Questions people ask

### How do you remember oxidation and reduction?

Use OIL RIG: Oxidation Is Loss, Reduction Is Gain, of electrons. A second memory trick links to oxygen: oxidation is gaining oxygen and reduction is losing it. In a reaction, the substance that loses electrons is oxidised and the one that gains is reduced.

### Why is metal extraction called reduction?

A metal ore is usually an oxide. The metal ions in it gain electrons to become metal atoms, or the oxide loses its oxygen. Both ways are reduction. Heating iron oxide with carbon removes the oxygen, so the iron is reduced and the carbon is oxidised.

## Related concepts

- [Oxidation](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-7/chemistry-school-part-7-concept-3)
- [Electrolysis](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-7/chemistry-school-part-7-concept-7)
- [Electrolyte](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-7/chemistry-school-part-7-concept-8)

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