Mixing of two solutions of soluble ionic solids (AX and BY), may result in a chemical reaction referred to as a precipitation.
This occurs if the mixture of solutions has the cation and anion of an insoluble compound (as AY below).
The water-insoluble solid is known as a precipitate because it separates from the solution.
The ions B+ and X– that remain in the solution are not changed and are referred to as spectator ions
The precipitate can be separated from the solution by filtration.
The soluble substance can be recovered by evaporation of the filtrate.
This occurs if the mixture of solutions has the cation and anion of an insoluble compound (as AY below).
 | + |  |  |  | ||
| AX(aq) | + | BY(aq) | | AY(s) | + | BX(aq) |
The water-insoluble solid is known as a precipitate because it separates from the solution.
The ions B+ and X– that remain in the solution are not changed and are referred to as spectator ions
The precipitate can be separated from the solution by filtration.
The soluble substance can be recovered by evaporation of the filtrate.