What occurs when sodium is added to liquid ammonia?
In ammoniacal solution, sodium metal eventually produces stoichiometric quantities sodium amide and dihydrogen gas. When the metal is introduced to the ammonia, a deep blue colour developes that is attributed to the solvated electron that eventually reduces the hydrogen of ammonia. Sometimes electrons couple to give a bronze colour. Preparative reactions in ammonia generally use a bit of iron salts to facilitate the electron transfer.
Note that the given equation is precisely equivalent to the reaction of water with sodium metal (in water, the lifetime of the solvated electron is much, much shorter!).