Final answer:
To form a precipitate with chloride ions in a solution, add silver ions (Ag⁺) to produce insoluble silver chloride (AgCl). Solubility rules guide this process, and the solubility of compounds can also be affected by pH, complex ion formation, or temperature adjustments.
Step-by-step explanation:
To precipitate chloride ions (β⁻) from a solution according to solubility rules, one should add a cation that forms an insoluble compound with Cl⁻. An example cation that leads to the formation of a precipitate is silver (Ag⁺) to form silver chloride (AgCl), which is insoluble in water. This is predicted by solubility rules that indicate all nitrate salts are soluble, but AgCl is an exception, being one of the insoluble compounds. When solutions of silver nitrate (AgNO₃) and sodium chloride (NaCl) are mixed, a precipitation reaction is expected, yielding a precipitate of AgCl while sodium nitrate (NaNO₃) remains in solution.
Using this understanding, one can also predict the precipitation of other ions. For example, if a solution contains the barium ion (Ba²⁺), adding sodium sulfate (Na₂SO₄) would cause the formation of barium sulfate (BaSO₄) as the expected precipitate due to its low solubility.
Furthermore, changing the pH, forming complex ions, or adjusting temperature can affect the solubility of certain precipitates, allowing for selective precipitation in a mixture of compounds.