A precipitation reaction is when two solutions react to make an insoluble substance.
The insoluble substance is known as a precipitate.
Precipitate reactions involve ions, so for the ions to collide the solutions must be liquid or molten.
- Barium Chloride + Sodium Sulfate -> Barium Sulfate + Sodium Chloride (aq)
Barium Sulfate is the precipitate.
Sodium Chloride is in solution.
You can tell its a precipitate reaction…