What is the role of sodium ions in the ion exchange process?

The role of sodium ions in the ion exchange process is to replace calcium and magnesium ions. This is particularly significant in water softening applications. In hard water, calcium (Ca²⁺) and magnesium (Mg²⁺) ions contribute to the hardness of the water, which can cause scaling in pipes, reduce the effectiveness of soaps and detergents, and lead to other issues.

The ion exchange process typically uses a resin that is loaded with sodium ions. When hard water passes through this resin, the calcium and magnesium ions in the water are exchanged for sodium ions. This effectively softens the water by reducing its hardness, as sodium ions do not produce the same problems associated with scaling as calcium and magnesium do.

Thus, the correct answer emphasizes the primary function of sodium in this process, highlighting its importance in making water more suitable for various uses by reducing hardness.