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Ammonium Bicarbonate also called bicarbonate of ammonia, ammonium hydrogen carbonate, hartshorn, or powdered baking ammonia is the bicarbonate salt of ammonia.
Ammonium bicarbonate 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
Properties
At room temperature Ammonium bicarbonate is a white, crystalline powder with a slight odour of ammonia that can dissolve in water to give a mildly alkaline solution. It is however insoluble in acetone and alcohols. Ammonium bicarbonate decomposes at 36 to 60 °C into ammonia, carbon dioxide and water vapor in an endothermic process (as it is with many ammonium salts) and so causes a drop in the temperature of the water. When reacted with acids carbon dioxide is produced, while reactions with alkalis give ammonia.
Uses
Ammonium bicarbonate was used in the food industry as a raising agent (e.g. for gingerbread) before the introduction of baking soda. This compound is used as a component in the production of fire-extinguishing compounds, pharmaceuticals, dyes, pigments and it is also a basic fertilizer being a source of ammonia. Ammonium bicarbonate is still widely used in the plastic and rubber industry, in the manifacture of ceramics, in chrome leather tanning and for the synthesis of catalysts.
Safety
Ammonium bicarbonate is irritant to the skin, eyes and respiratory system.
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