What do you mean by a precipitation reaction?

Precipitation reactions occur when cations and anions in aqueous solution combine to form an insoluble ionic solid called a precipitate. A precipitate is a solid that forms out of solution. A common example is that of the mixing of two clear solutions: Silver nitrate (AgNO3) and sodium chloride (NaCl): AgNO3(aq) + NaCl(aq) → AgCl(s)↓ + NaNO3(aq) The precipitate forms because the solid (AgCl) is insoluble in water.