Solubility rules predict which ionic compounds dissolve in water. Generally, salts containing Group 1 cations (Li+, Na+, K+, etc.), ammonium (NH4+), nitrates (NO3−), acetates (C2H3O2−), chlorates (ClO3−), and perchlorates (ClO4−) are soluble. Most chlorides, bromides, and iodides are also soluble, with notable exceptions for chlorides of silver, lead, mercury, and a few others. Most sulfates are soluble, except those of barium, strontium, calcium (to some extent), lead, silver, and mercury. Hydroxides are generally insoluble except for alkali metal hydroxides and the heavier alkaline earth hydroxides at least to a limited extent; carbonates, oxalates, chromates, and phosphates are typically insoluble except with Group 1 cations and ammonium. If you’d like, I can tailor the list to a specific set of ions or compile a quick reference chart for your class or lab.
