Which of the following is used to reduce hardness due to chlorides and sulfates?

Lime soda softening is a process specifically designed to reduce hardness in water, particularly hardness caused by calcium and magnesium ions. While the question mentions chlorides and sulfates, it’s important to understand that lime soda softening primarily targets the removal of hardness-causing ions through the addition of lime (calcium hydroxide) and soda ash (sodium carbonate). This process leads to the precipitation of calcium and magnesium as carbonates, which can be removed from the water.

In contexts where chlorides and sulfates are present, lime soda softening can also indirectly influence these compounds due to changes in pH and the precipitation of other associated ions. However, the treatment method that mainly addresses the broader aspect of water hardness and does incorporate the complexities of mineral interactions is lime soda softening.

Other methods listed, such as reverse osmosis, while effective in removing a wide range of contaminants including ions responsible for hardness, do not specifically target the hardness reduction attributed to chlorides and sulfates. Filtration generally focuses on particulate removal rather than ion-based changes in water hardness, and activated carbon treatment primarily addresses organic contaminants and tastes or odors rather than directly impacting hardness levels. Therefore, lime soda softening stands out as the most applicable method for managing hardness in