Qualitative analysis in chemistry is a method used to determine the ions present in a solution chiefly by means of chemical reactions.
In this case, I suspect the presence of silver ions and/or barium ions. The first step is to add dilute HCl. This will lead to the precipitation of the silver ion as AgCl. If a white precipitate is formed upon addition of HCl then Ag^+ is present in the solution.
Secondly, I add a carbonate such as NH4CO3(aq). This will cause the barium ions to become precipitated as barium carbonate. Hence, the formation of a white precipitate when NH4CO3(aq) is added to the solution indicates the presence of barium ion in the solution.
