What do you mean by a precipitation reaction? Explain by giving examples.

Explanation

On mixing the clear solutions of two ionic compounds, a substance which is insoluble in water, is formed. This insoluble substance formed is known as precipitate. Any reaction that produces a precipitate is called a precipitation reaction.
When sodium sulphate solution is mixed with barium chloride solution, a white substance `BaSO_(4)` is formed.
`Na_(2)SO_(4)(aq)+BaCl_(2)(aq)rarrBaSO_(4)(s)darr+2NaCl(aq)`
The white precipitate of `BaSO_(4)` is formed by the reaction of `SO_(4)^(2-)andBa^(2+)`. The other product formed is sodium chloride which remains in the solution.