Solubility Rules

Sulfides are generally insoluble, except for those of alkali metals (e.g., Na2S, K2S) and BaS.

Most hydroxides are insoluble, except for those of alkali metals and some alkaline earth metals like Ba(OH)2.

Potassium hydroxide (KOH) is soluble in water.

Potassium permanganate (KMnO4) is soluble in water.

Magnesium hydroxide (Mg(OH)2) is generally considered insoluble.

Zinc hydroxide (Zn(OH)2) is insoluble in water.

Nitrates are generally soluble in water.

Most chlorides are soluble, except for those of silver (AgCl), lead (PbCl2), and mercury (Hg2Cl2).

Most carbonates are insoluble, except for those of alkali metals and ammonium (NH4+).

Most sulfates are soluble, except for those of barium (BaSO4), lead (PbSO4), and calcium (CaSO4).