You are gien a group I unkown and are told that it contains only one cation. You treat it with HCL and get a white precipitate, and then you wash the precipitate with cold water. You are allowed to treat the washed precipitate with one more reagent. By observing what happens when this one reagent is added you should be able to decide, within seconds, what cation is present in your unknown.
What one reagent is added?
When this reagent is added, what would you observe if your unknown contains:
a. Ag+
b.Pb+
c.Hg22+