Britannica Sources used in this answer

What products form when an alkali metal reacts with water?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — alkali metal Modern version of the periodic table of the elements (printable).

When an alkali metal reacts with water, the reaction produces an alkali metal hydroxide and hydrogen gas.1

This chemical process is represented by the following equation, where M represents the alkali metal:

$M + H_{2} O \to M O H + 1 / 2 H_{2}$

These reactions are highly exothermic, meaning they release significant heat. Because the hydrogen generated can react with oxygen, the process can become explosive, particularly when small metal droplets or thin films are involved. The rate of this reaction increases with the atomic weight of the metal, and because the resulting hydroxides are highly soluble, they are easily removed from the metal's surface, allowing the reaction to proceed with continued vigor.1