# Metal and acid reaction

A reactive metal reacts with an acid to make a salt and hydrogen gas. The fizzing is hydrogen forming.

Chemistry (school) · Part 06: Acids, bases and salts · Card 9 of 9 · Last updated 2026-10-19

## Analogy

The metal swaps places with the hydrogen in the acid and the hydrogen bubbles off.

## Example

**Metal + acid**

Mg + 2HCl -> MgCl2 + H2
Test for hydrogen: a lit splint gives a squeaky pop

## In practice

Magnesium fizzes quickly in hydrochloric acid. Copper does not react at all.

## Practice

### Flashcards

- **What is made when a metal reacts with an acid?** A salt and hydrogen.

## Questions people ask

### How do you test for hydrogen gas?

Hold a lit splint at the mouth of a test tube of the gas. Hydrogen burns with a squeaky pop sound. The pop is a tiny explosion as hydrogen combines with oxygen from the air to make water. Never test large amounts of hydrogen this way.

### Why does copper not react with dilute acids?

Copper is below hydrogen in the reactivity series, so it cannot push hydrogen out of an acid. Only metals above hydrogen, such as magnesium, zinc and iron, react. The more reactive the metal, the faster the bubbles form. Potassium would react dangerously.

## Related concepts

- [Salt](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-6/chemistry-school-part-6-concept-6)

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