A solution may contain \(\mathrm{Ag}^{+}, \mathrm{Pb}^{2+},\) and/or
\(\mathrm{Hg}_{2}^{2+} .\) A white precipitate forms on addition of \(6
\mathrm{M}\) HCI. The precipitate is insoluble in hot water. The residue tums
black on addition of ammonia. Which of the ions are present, which are absent,
and which remain undetermined? State your reasoning. Note: On paper unknowns
such as this one, confirmatory tests are usually not included.
Present
Absent
In doubt
