# 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?

Jun 22, 2017

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. $P b C r {O}_{4}$, $B a C r {O}_{4}$, $A {g}_{2} C r {O}_{4}$, $Z n C r {O}_{4}$, especially dications such as $P {b}^{2 +}$ or $B {a}^{2 +}$.....

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

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

$\text{All the salts of the alkali metals and ammonium are soluble.}$

$\text{All nitrates, and perchlorates are soluble.}$

$\text{All halides are soluble EXCEPT for}$  AgX, Hg_2X_2, PbX_2".

$\text{All sulfates are soluble EXCEPT for}$ $P b S {O}_{4} , B a S {O}_{4} , H g S {O}_{4}$.

$\text{All carbonates and hydroxides are insoluble.}$

$\text{All sulfides are insoluble.}$

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 \text{kalignost}, i.e. $\text{potassium recognizer}$.............