What is the main compound removed in the ion exchange process?

The ion exchange process primarily targets the removal of specific ions from water, making the elimination of calcium ions a central focus, particularly in the context of softening water. Calcium carbonate, a common form of hardness in water, contributes to scale formation and various operational challenges in water systems. By utilizing ion exchange, calcium ions are replaced by sodium ions, effectively reducing water hardness.

This process is crucial because high levels of calcium carbonate can lead to issues in plumbing and equipment, reducing their efficiency and lifespan. Ion exchange systems, often used in water softeners, facilitate this critical exchange, ensuring that the resultant water is less prone to scale and better suited for household or industrial use.

The other options listed do not represent the primary target of the ion exchange process. Chlorine is typically removed by different methods such as activated carbon or chemical dechlorination. Sodium chloride is not removed but rather used as a regenerating agent in the ion exchange system. Silica gel is involved in different filtration processes, primarily focused on removing specific impurities rather than the calcium ions prevalent in hardness.