You are given the four solids, K₂CO₃, CaO, ZnSO₄, and BaCO₃, and three solvents, H₂O(l), HCl(aq), and H₂SO₄(aq). You are asked to prepare four solutions, each containing one of the four cations, that is, one with K⁺(aq), one with Ca²⁺(aq), and so on. Using water as your first choice, what solvent would you use to prepare each solution? Explain your choices.