Hard water can be softened by washing soda or sodium carbonate Na2CO3 . It removes the calcium ions in a precipitation reaction from the hard water. And then the hard water passed through an ion-exchange resin in a column. In the water, sodium ions replace the calcium ions when it passes through the column. Water is categorized into two types. They are hard, and soft water. Hard water- water with naturally present minerals like magnesium and calcium. These are beneficial for health. Soft water- it is left with only cations, and that is sodium. It has a salty taste. Do not leave any spots on dishes after wash. Soap is easily effective.