Ammonium hydroxide is a name sometimes given to an aqueous solution of ammonia. Ammonia, when dissolved in water, can be protonated. Hence ammonium and hydroxide ions will be present in an aqueous solution of ammonia according to the following equilibrium:

NH₃ + H₂O → NH₄⁺ + OH^-

With a base ionization constant (K_b) of 1.8×10^-5, in a 1M ammonia solution about 0.42% of the ammonia will be protonated to ammonium ions (equivalent to a pH of 11.63).

Aqueous ammonium hydroxide can also dissolve various metal oxides and hydroxides, such as copper(II) hydroxide to form ammine complexes. Solutions of ammonium hydroxide can also dissolve reactive metals such as aluminum and zinc, with the liberation of hydrogen gas. When ammonium hydroxide is mixed with dilute hydrogen peroxide in the presence of a metal ion, such as Cu²⁺, the peroxide will undergo rapid decomposition.

See also

• Conjugate acid

External links

Ammonium compounds | Bases

ammoniakvand | Ammoniumhydroxid | Ammoniaque | Wodorotlenek amonu | Гидроксид аммония | Ammoniumhydroxid