Over eighty-five percent of the homes in the U.S. and Canada have water that is at least this hard. Hard water requires more soap and detergent for laundering, cleaning and bathing because suds do not form as well in hard water. The reaction between soap and hard water results in a greasy, curd-like, deposit which makes fabrics feel harsh and leaves water spots on dishes and utensils. Mineral scale builds up in hot water appliances and industrial boilers, reducing energy efficiency and shortening appliance and equipment life. Water is softened by removing the calcium and magnesium ions from hard water and replacing them with sodium ions.
Water softeners use cation exchange resin to exchange sodium ions for calcium and magnesium ions.
As supply water flows through the resin bed, the exchange takes place and the water becomes soft. Activity A - Ionic Properties 1. Review with students the ionic bonds involved in the formation of NaCl. Determine the ionic charge of Na and Cl in solution. To demonstrate this process an electrolysis experiment can be designed.