The reactivity of metalsReactions of metals with water

The reactivity series lists metals from the most reactive to the least reactive. A metal can displace a less reactive metal from its compounds. This is useful for extracting metals from their oxides.

Part ofScienceChemical changes

Reactions of metals with water

When metals react with water, metal hydroxides and hydrogen gas are formed.

Image caption,
Potassium reacts quickly with water producing a lilac-coloured flame

For example, when potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The metal self-ignites, which also ignites the hydrogen gas. This results in sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.

This can be represented in different ways as shown:

Word equation

potassium + water → potassium hydroxide + hydrogen

Chemical equation

2 K(s) + 2 H2O(l) → 2 KOH(aq) + H2(g)