Question

How do I know which salts are soluble in water? What generalization exists for chromate salts, i.e. salts of `CrO_4^(2-)`, and other salts?

Answer 1

Well, chemistry is an experimental science.........which of course is determined by EXPERIMENT.

Explanation:

And it is a fact that chromate ion forms water-insoluble salts when treated with most heavy metals........, i.e. `PbCrO_4`, `BaCrO_4`, `Ag_2CrO_4`, `ZnCrO_4`, especially dications such as `Pb^(2+)` or `Ba^(2+)`.....

On the other hand, the salts of alkali metal are MOSTLY soluble.....

And in aqueous solution.....we can propose the following generalities....

`"All the salts of the alkali metals and ammonium are soluble."`

`"All nitrates, and perchlorates are soluble."`

`"All halides are soluble EXCEPT for"` # AgX, Hg_2X_2, PbX_2"#.

`"All sulfates are soluble EXCEPT for"` `PbSO_4, BaSO_4, HgSO_4`.

`"All carbonates and hydroxides are insoluble."`

`"All sulfides are insoluble."`

The given rules follow a hierarchy. Alkali metal and ammonium salts tend to be soluble in all circumstances. The one exception to this rule is `K^(+)""^(-)BPh_4` and `NH_4^(+)""^(-)BPh_4`, both of which are as soluble as bricks. `Na^+""^(-)BPh_4`, the which has some aqueous solubility, is sold as `"kalignost"`, i.e. `"potassium recognizer"`.............