One type of water softener is precipitation softening, also known as ion-exchange. Based on the reactants used (Na2CO3 and CaCl2), what ions would remain in the softened water that would be consumed by the homeowners? What could be some negative aspects of consuming these ions?

In ion exchange softener, the minerals of hard water are in the form of ions of Mg⁺² and Ca⁺². They are replaced by Na⁺ ion. The Na⁺ that resides on the bed of resin used in ion exchange softener make all heavy ions like Mg⁺² and Ca⁺². In this way all the hard ions of hard water are removed and they are replaced by Na⁺ ion. hard ions are removed because they form insoluble compounds so they are precipitated out.

The ion that remains in soft water is Na⁺ ion.

The negative aspect of consuming this ion is that it is harmful for those suffering from heart ailment like heart pressure.