Which of the following combinations will likely result in the formation of a precipitate? (Select all the apply)

1) Mixing a BaCl₂ solution with a K₂SO₄ solution.

2) Mixing a Na₃PO₄ solution with a CaCl₂ solution.

3) Mixing a NaNO₃ solution with a CuSO₄ solution.

4) Mixing an (NH₄)₂CO₃ solution with a KOH solution.

5) Mixing a Na₂S solution with a Pb(NO₃)₂ solution.