When reacting with a base, Zn(OH) 2 dissolves by the formation of a complex, Zn(OH) 4 2 . In the reaction
with an acid, protons are transferred from H 3 O to the hydroxide ions, forming water molecules
that remain coordinated to the Zn 2 ion.
The behavior of Zn 2 in liquid ammonia is analogous to that in water. First a precipitate of Zn(NH 2 ) 2
forms when an amide is added, but the precipitate dissolves when either a solution containing NH 4
or NH 2 is added. This behavior can be shown as follows: