"Hard" water is hard because it contains Ca2+(aq) and Mg2+(aq) ions. It  can be softened by adding borax powder, which is sodium tetraborate,  Na2B4O7. Adding borax removes the Ca2+(aq) and Mg2+(aq) from solution.  Write a net ionic equation for each of these two reactions. What ion  replaces the Ca2+(aq) and Mg2+(aq) ions in the water?