How do we test for the presence of ammonium ion in aqueous solution? Will there be other ions in solution?

1 Answer
Feb 11, 2016

Why will there be other ions? Because your sample will contain at least one other ion in addition to ammonium given that the solution is electrostatically neutral.

Explanation:

When you have several unknowns in a sample, you try to separate the metal ions from each other according to some scheme. Of course, you CANNOT separate anion from cation.

Now I don't know the characterizing test you are using. Typically, it is to take treat the solution with hydroxide, and treat it with hydroxide base.

#NH_4^+ + HO^(-) rarr NH_3uarr + H_2O#

The pungent odour of ammonia is characteristic and very indentifiable. The problem is that whatever the ammonium counterion is (halide or something else) has still to be identified. We have to start the scheme again.

Does this address your question? If you give some more details, someone here will try to qualify this answer.