What is #"ammonium hydroxide"#?

1 Answer
Jun 8, 2017

Well first you will have to define your terms........

Explanation:

Ammonia is a colourless gas with a foul penetrating odour. It is VERY soluble in liquid water, and conc. ammonia is approx. #15*mol*L^-1# concentration. Fisher sells this reagent as #"ammonium hydroxide"#; a better name for the reagent would be simply #"aqueous ammonia"#, because the following acid-base reaction lies STRONGLY to the LEFT:

#NH_3(aq) + H_2O(l) rightleftharpoonsNH_4^(+) + HO^-#

The bulk of the material in solution is still #NH_3#.

On the other hand I could take equivalent quantities of ammonia gas, and hydrogen chloride gas, and get the SALT, #"ammonium chloride"#, i.e.

#NH_3(g) + HCl(g)rarrNH_4Cl(s)darr#

So the moral? #"ammonium hydroxide"-=NH_4OH-=NH_3*H_2O#.

Aqueous ammonia, #NH_3*H_2O#, has the same formulation as #NH_4OH#, i.e. #NH_5O#. Capisce?