[kihogofi]

Given a set of arbitrary compounds, how can it be determined which of said compounds have the lowest solubility in water?

E.g. if the compounds were, K3PO4, Fe(NO3)2), Hg2Cl2, Na2CO3, CuCl2; how would it be determined that Hg2Cl2 is the compound that has the lowest solubility in water?

Thanks in advance!

[AWK]

Qualitative analysis of cations uses a set of several rules that are easy to remember, among others chlorides of the 1st cation group are not dissolved in cold water.