What happens when sodium is treated with ammonia?

A very beautiful inorganic reaction occurs that mirrors the (given) reaction of sodium metal with water…

[math]Na(s) + H_{2}O(l) longrightarrow NaOH(aq) + dfrac{1}{2}H_{2}(g)uparrow [/math]

And with liquid ammonia…

[math]Na(s) + NH_{3}(l) longrightarrow NaNH_{2}(ammoniacal) + dfrac{1}{2}H_{2}(g)uparrow [/math]

When the metal is first added to ammonia you see a brilliant purple colour … and this is proposed to be due to a (long-lived) solvated electron … that performs the reduction…

Solutions of sodium in liquid NH3 are blue in colour. There is formation of ammoniated sodium metal ion and ammoniated electron. These are responsible for the electrical conductivity and reducing property.

Na= Na+ + e-

Na+ +xNH3 = [ Na( NH3)x]+

e- + yNH3 = [ e( NH3) y]—

Sodium reacts with dry NH3 to give sodamide.

2Na+ 2NH3 =2 NaNH2 + H2