# What ion do alkalis form when added to water?

Nov 21, 2016

They form alkali metal cations and hydroxide ions.

#### Explanation:

And we represent this by the given reaction:

$M \left(s\right) + {H}_{2} O \left(l\right) \rightarrow {M}^{+} \left(a q\right) + H {O}^{-} \left(a q\right) + \frac{1}{2} {H}_{2} \left(g\right)$

$M = L i , N a , K , e t c .$

The alkali metals become increasingly more reactive as we descend the Group.