What is a precipitation rule, and how is it used to predict whether a precipitate will form?

• A. A precipitation rule states all chlorides are insoluble.
• B. Solubility rules tell which salts are soluble or insoluble; if the combination yields an insoluble salt, a precipitate forms.
• C. Solubility rules predict color changes.
• D. Precipitation rules apply only to gaseous reactions.

Answer: (B)