SOLUBILITY RULES

SOLUBLE COMPOUNDS

1. Almost ALL Na⁺, K⁺ and NH₄⁺ are soluble, this means they completely dissociate in water.

2. Salts of NO₃^-, ClO₃^-, ClO₄^-, and acetate, C₂H₃O₂^- are soluble, except for acetates of Al³⁺ and Ag¹⁺, which are insoluble.

3. Almost all salts of the halogens Cl^-, Br^-, I^- are soluble except when combing with Ag¹⁺, Pb²⁺ and mercury(I), Hg₂²⁺.

4. Compounds containing the fluoride ion, F^- are soluble except for group IIA cations and Pb^2+. These cations will precipitate out as a fluoride salt.

5. Salts of sulfate, SO₄^2- are soluble except for the group IIA lighter metals, Ca²⁺, Ba²⁺, Sr²⁺ and Pb²⁺.

INSOLUBLE COMPOUNDS

1. Most salts of carbonates (CO₃^2-), phosphates (PO₄^3-), oxalates (C₂O₄^2-) and chromates (CrO₄^2-) are insoluble, except for salts of ammonium (NH₄⁺) and group IA cations.

2. Most metal sulfides ( S^2-) precipitate out, they are insoluble.

3. Most metal hydroxides and oxides are insoluble, think rocks. However Ba(OH)₂ is pretty soluble.