The alkali metals react with most non-metals to form hydrides, oxides, sulphides, carbides, phosphides and other compounds. The binary compounds of all alkali metals are ionic with `M^(+)` cations. The alkali metals easily ionize and readily reduce hydrogen ions. They react with ammonia to evolve hydrogen and form blue coloured solutions.
`2M(s) + 2H_2O (l) to 2MOH(aq) + H_2(g)`
`2M(s) + 2NH_3 (l) to 2MNH_2(am) + H_2(g)`
Why do alkali metals dissolve in liquid ammonia to give blue coloured solutions ?

Explanation

The ammoniated electrons are responsible for the blue colour of the solution .
`M+(x+y)NH_3 to [M(NH_3)_x]^(+)+ underset("Ammoniated electrons")([e(NH_3)_y]^(-)`