Editing Ammonia (section)

=== Amphotericity ===
One of the most characteristic properties of ammonia is its [[basicity]]. Ammonia is considered to be a weak base. It combines with [[acid]]s to form [[ammonium]] [[salt (chemistry)|salt]]s; thus, with [[hydrochloric acid]] it forms [[ammonium chloride]] (sal ammoniac); with [[nitric acid]], [[ammonium nitrate]], etc. Perfectly dry ammonia gas will not combine with perfectly dry [[hydrogen chloride]] gas; moisture is necessary to bring about the reaction.{{sfn|Chisholm|1911|p=862}}<ref>{{cite journal|title=Influence of moisture on chemical change|author=Baker, H. B. |year=1894|journal=J. Chem. Soc.|volume=65|pages= 611–624|doi=10.1039/CT8946500611|url=https://zenodo.org/record/1863586 }}</ref>

As a demonstration experiment under air with ambient moisture, opened bottles of concentrated ammonia and [[hydrochloric acid]] solutions produce a cloud of [[ammonium chloride]], which seems to appear 'out of nothing' as the salt [[aerosol]] forms where the two [[diffusion|diffusing]] clouds of reagents meet between the two bottles.
{{block indent| {{chem2|NH3 + HCl → [NH4]Cl}}}}

The salts produced by the action of ammonia on acids are known as the [[:Category:Ammonium compounds|ammonium salts]] and all contain the [[ammonium ion]] ({{chem2|[NH4]+}}).{{sfn|Chisholm|1911|p=862}}

Although ammonia is well known as a weak base, it can also act as an extremely weak acid. It is a [[protic|protic substance]] and is capable of formation of [[amide]]s (which contain the {{chem2|NH2−}} ion). For example, [[lithium]] dissolves in [[liquid ammonia]] to give a blue solution ([[solvated electron]]) of [[lithium amide]]:
{{block indent| {{chem2|2 Li + 2 NH3 → 2 LiNH2 + H2}}}}