GENERAL SOLUBILITY RULES

Few things are absolutely insoluble, but many are so for most practical purposes. The following rules can serve as a rough guide.

The following are soluble in water:

1. All simple Na⁺, K⁺, and NH₄⁺ compounds.

2. All nitrates and acetates. {Bi(NO₃)₃ and most acetates hydrolyze to slightly soluble products.]

3. All chlorides except Pb²⁺, Ag⁺, Hg₂²⁺, and Cu⁺. (Sb³⁺, As³⁺, Bi³⁺, Sn²⁺, and Sn⁴⁺ chlorides hydrolyze to insoluble products.)

4. All sulfates except Pb²⁺, Ag⁺, Hg₂²⁺, Ba²⁺, Ca²⁺, and Sr²⁺.

The following are essentially insoluble in water:

1. All metals except Na, K, Ba, and Sr which react with H₂O.

2. All oxides and hydroxides except Na⁺, K⁺, NH₄⁺.

(Ba²⁺ , Ca²⁺ , Mg²⁺ , and Sr²⁺ oxides react with water to form slightly soluble hydroxides.)

3. All sulfides, oxalates, phosphates, carbonates, and silicates except those of Na⁺, K⁺, and NH₄⁺. (Most acetates, the soluble silicates, and the sulfides of Ba²⁺ , Ca²⁺ , and Sr²⁺ hydrolyze to insoluble products.)