Solubility Rules
Solubility rules tell you whether an ionic compound stays dissolved in water or forms a solid precipitate. You need them for double-replacement reactions, net ionic equations, and lab predictions.
Key Facts to Memorize
Group 1 and ammonium
Li⁺, Na⁺, K⁺, NH₄⁺ salts are ALWAYS soluble. No exceptions.
Nitrates, acetates, chlorates
NO₃⁻, C₂H₃O₂⁻, ClO₃⁻ are always soluble.
Halides
Cl⁻, Br⁻, I⁻ are soluble EXCEPT with Ag⁺, Pb²⁺, Hg₂²⁺.
Sulfates
SO₄²⁻ is soluble EXCEPT with Ba²⁺, Pb²⁺, Ca²⁺, Sr²⁺, Ag⁺.
Carbonates and phosphates
Insoluble except with Group 1 and ammonium.
Hydroxides
Insoluble except Group 1, and slightly soluble with Ca²⁺, Sr²⁺, Ba²⁺.
Sulfides
Insoluble except Group 1, Group 2, and ammonium.
Al says…
Start with the 'always soluble' list. If both products are on it, no reaction happens — and that's a real answer worth points.
Practice This Topic
External Tools
- Blooket review game
Coming soon — Mrs. Cauthron will post the game link here.
- ChemCollective virtual lab
Mix solutions and watch precipitates form.