Selective Precipitation
The separation of ions from a mixture by adding a reagent that precipitates them one at a time.
Unit
mol/L
In depth
Because the ions have different solubility products, the least soluble compound precipitates first and can be filtered off before the next begins to appear. Careful control of reagent concentration — often by controlling pH — makes very clean separations possible.
Examples in the real world
Passing H₂S into acidified solution precipitates CuS but leaves ZnS dissolved until the solution is made alkaline.