Question

What ions are found in hard water? What happens when water is "softened"?

Short answer

Hard water contains calcium (Ca^2+) and magnesium (Mg^2+) ions. Water softening involves removing these ions and replacing them with sodium ions (Na^+). This process reduces scale formation, improves soap lathering, and prevents buildup in pipes, ultimately enhancing cleaning and increasing the efficiency and lifespan of appliances and plumbing systems.

Step-by-step solution

Identify the ions found in hard water.

Hard water contains high concentrations of dissolved minerals, primarily calcium (Ca) and magnesium (Mg), in the form of Ca^2+ and Mg^2+ ions. These ions can come from natural sources such as dissolved limestone and dolomite in the water. The presence of these ions in the water leads to various problems, such as the formation of scale on appliances, reduced effectiveness of soaps and detergents, and clogging of pipes.

Explain the process of water softening.

Water softening is a process that removes the calcium and magnesium ions, which are responsible for water hardness, and replaces them with sodium ions (Na^+). One common method used for water softening is called ion exchange. In this process, hard water passes through a bed of resin beads that are charged with sodium ions (Na^+). The calcium and magnesium ions are attracted to the negatively charged resin beads, effectively exchanging places with the sodium ions. The result is softened water containing more sodium ions and fewer calcium and magnesium ions.

Describe what happens when water is softened.

When water is softened, the calcium (Ca^2+) and magnesium (Mg^2+) ions are removed and replaced with sodium (Na^+) ions. This results in water with a lower concentration of hardness ions and a higher concentration of sodium ions. The softened water is more effective for cleaning purposes, as it reduces the formation of scale on appliances, improves the lathering of soaps and detergents, and prevents buildup in pipes. Additionally, using softened water can extend the lifetime of appliances and plumbing systems, as well as contribute to more efficient energy usage.