We know that bottles 1 and 3 are cations. Cations are positively charged ions. Thus, Pb+2 and Ag+ could be bottles 1 and 3.
Likewise, we know that bottle 2 and 4 are anions. Anions are negatively charged ions. Thus, Cl- and SO4-2 could be bottle 2 and 4.
Precipitates are solids that fall out of a liquid solution that is made from two soluble salts. A salt is composed of a cation and anion. Thus, the following salts are possible in this lab with the reagents that are given. A solubility table was used to determine whether or not each possible salt is soluble or insoluble.
- PbCl2 = Soluble
- PbSO4 =Insoluble
- AgCl = Insoluble
- (Ag)2SO4 = Slightly soluble
Therefore, some sort of precipitate will form when lead (II) and sulfate are mixed, silver (I) and chloride are mixed, and when silver (I) and sulfate are mixed.
Thus, the bottles can be identified as follows:
- Bottle 1 must be Ag+ because it is found in two of the insoluble products.
- Bottle 3 must be Pb+2 because it is the only other cation that is left.
- Bottle 2 must be SO4-2 because it is the only anion that is involved in the formation precipitate formation.
- Thus, out of the process of elimination, bottle 4 must be Cl-.
This should be sufficient information to complete your table.