Letters a and c are both likely to form precipitates.Ĭoncerning a) CaSO 4, although sulfates tend to be soluble, Rule #5 indicates that calcium sulfate is an important exception to this rule.įor b), Rule #1 indicates that table salt (NaCl) is soluble because it is a salt of an alkali metal.Ĭ) is an example of two rules contradicting each other. Which of these substances is likely to form a precipitate? Therefore, it will not form a precipitate.ģ. This is perchlorate, which according to Rule #2 is likely to be soluble. Therefore, FeCO 3 is likely to form a precipitate.Ģ. Fluorides such as BaF 2, MgF 2, and PbF 2 are frequently insoluble.Īccording to Rule #5, carbonates tend to be insoluble.Phosphates such as Ca 3(PO 4) 2 and Ag 3PO 4 are frequently insoluble.Group II carbonates (CaCO 3, SrCO 3, and BaCO 3) are insoluble, as are FeCO 3 and PbCO 3. Arsenic, antimony, bismuth, and lead sulfides are also insoluble. Most sulfides of transition metals are highly insoluble, including CdS, FeS, ZnS, and Ag 2S.Thus, Fe(OH) 3, Al(OH) 3, Co(OH) 2 are not soluble. Hydroxide salts of transition metals and Al 3 + are insoluble. Hydroxide salts of Group II elements (Ca, Sr, and Ba) are slightly soluble. Hydroxide salts of Group I elements are soluble. Most hydroxide salts are only slightly soluble.Important exceptions to this rule include CaSO 4, BaSO 4, PbSO 4, Ag 2SO 4 and SrSO 4. AgNO 3 and Ag(C 2H 3O 2) are common soluble salts of silver virtually all others are insoluble. Thus, AgCl, PbBr 2, and Hg 2Cl 2 are insoluble. Important exceptions to this rule are halide salts of Ag +, Pb 2 +, and (Hg 2) 2+. Salts containing Cl -, Br -, or I - are generally soluble.Salts containing nitrate ion (NO 3 -) are generally soluble.Salts containing the ammonium ion (NH 4 +) are also soluble. Salts containing Group I elements (Li +, Na +, K +, Cs +, Rb +) are soluble.If there two rules appear to contradict each other, the preceding rule takes precedence. The following are the solubility rules for common ionic solids.

Ag2so3 precipitate color