Chemical precipitation is the formation of a (liquid, solid, or solute) from a solution. in a precipitation reaction, the precipitate(dissolves in, melts in, or separates from) the solution.

Chemical precipitation is the formation of a solid from a solution. In a precipitation reaction, the precipitate separates from the solution.

Explanation:

Some reactions that happen in aqueous solutions produce precipitate. The precipitate is a solid compound formed by the chemical combination of ions, which is not soluble. In brief, a solid produced during a chemical reaction is a precipitate.

An example of a precipitation reaction is the double replacement reaction between sodium hydroxide and copper(II) chloride, which is represented by this equation:

     2NaOH (aq) + CuCl₂ (aq) → 2NaCl (aq) + Cu(OH)₂ (s).

                                                                                ↑

                                                                        precipitate

The reactants, NaOH and CuCl₂ (aq) are in aqueous solutions, which is indicated adding  (aq) to the right of the chemical formula, the product NaCl, being a soluble salt, remain in solution, which is also indicated by the use of (aq), but the product Cu(OH)₂ is insoluble, and forms the precipitate, which is showm by the use of (s).