Which compound is insoluble in water?

Core Concept

Chlorides are generally soluble, but silver chloride is one of the named exceptions, so it precipitates whenever Ag⁺ meets Cl⁻ in solution. Sodium, potassium, and ammonium salts carry unconditional solubility, and every nitrate dissolves without exception. Knowing the exception list for halides (silver, lead, mercury(I)) resolves most precipitation predictions quickly.