What is precipitation reaction ? i did not understand it.
When during a chemical reaction, an insoluble solid product is formed which can be separated from the solution by filtration, then the solid product is known as precipitate and the reaction is known as precipitation reaction. For example, when a solution of sodium chloride is added to a solution of silver nitrate, then a white precipitate of silver chloride is formed.
NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl (↓)