Solubility Rules

 

 

All nitrate (NO3-) salts are soluble.

 

All salts of alkali metals (IA) (e.g., Na+,K+) and ammonium, NH4+ are soluble.

 

Most chloride salts are soluble. Exceptions are AgCl, PbCl2 and Hg2Cl2.

 

Most acetate, C2H3O2-, chlorate, ClO3- and perchlorate, ClO4- salts are soluble.

 

Most sulfate salts are soluble. Exceptions are SrSO4, BaSO4, PbSO4 and CaSO4,

 

Most hydroxide compounds are only slightly soluble*. Exceptions are the alkali metal hydroxides and ammonium hydroxide. Sr(OH)2, Ba(OH)2 and Ca(OH)2 are only moderately soluble.

 

Most sulfide (S2-), carbonate, (CO32-) and phosphate (PO43-) salts are only slightly soluble*.

 

All common acids are assumed soluble.

 

Most cyanide, CN- and sulfite, SO32- salts are soluble.

 

For salts not mentioned, look for family resemblance and patterns.

 

 

* For predicting precipitation, slightly soluble and insoluble essentially mean the same thing. Tiny amounts that dissolve are not usually detected by the naked eye.