Ammonium Bicarbonate

Ammonium bicarbonate, NH₄HCO₃, is formed as shown above and also by passing carbon dioxide through a solution of the normal compound, when it is deposited as a white powder, which has no smell and is only slightly soluble in water. The aqueous solution of this salt liberates carbon dioxide on exposure to air or on heating, and becomes alkaline in reaction. The aqueous solutions of all the carbonates when boiled undergo decomposition with liberation of ammonia and of carbon dioxide:

:NH₄HCO₃ → NH₃ + H₂O + CO₂

It is therefore occasionally used as baking powder, e.g. for gingerbread.