Question

How do silver ions interact with halide ions? How can the presence of ammonium in aqueous solution be evidenced?

Answer 1

`Ag^+ + Cl^(-) rarr AgCl(s)darr`

Explanation:

Of course, the equation presupposed the ABSENCE of other metal ions that form insoluble halides, i.e. we assume the absence of `Pb^(2+)`, and `Hg_2^(2+)` ions.............

For ammonium ions, we could exploit the acid-base properties of ammonium cation:

`NH_4^+ + HO^(-) rarr NH_3(g)uarr + H_2O(l)`

The odour of ammonia is unmistakable. Ammonium forms an insoluble tetraphenylborate, `NH_4BPh_4`, but tetraphenylborate salts are VERY expensive, and tend not to be used in this scenario.