Solubility Rules
A set of empirical guidelines predicting whether an ionic compound will dissolve appreciably in water.
Unit
Dimensionless
In depth
All nitrates, acetates and group 1 and ammonium salts are soluble; most chlorides are soluble except those of silver, lead and mercury(I); most sulfates are soluble except those of barium, lead and calcium; most carbonates, phosphates, sulfides and hydroxides are insoluble. The rules let precipitation be predicted without any calculation.
Examples in the real world
Mixing Pb(NO₃)₂ with KI gives a bright yellow PbI₂ precipitate, since iodides of lead are insoluble.