Which of the following is the principal scale-forming substance in water?

Which of the following is the principal scale-forming substance in water?

• A. Magnesium sulfate
• B. Calcium carbonate
• C. Sodium chloride
• D. Silica

Answer: (B)

Calcium carbonate is the principal scale-forming substance in water, particularly in the context of water treatment and distribution systems. The formation of scale primarily occurs when there is a change in conditions, such as temperature or pressure, that favors the precipitation of calcium carbonate from the water. This can happen when water becomes supersaturated with calcium ions and carbonate ions. The tendency of water to form scale from calcium carbonate is significant because it can cause problems in pipes, boilers, and cooling systems, leading to reduced efficiency and potential damage. It is a common component of hard water, which can lead to scaling on surfaces, fixtures, and within plumbing systems. Other substances listed, while they can also affect the quality of water or the scaling process, do not rank as the primary scale-forming compounds in standard water treatment contexts. For example, magnesium sulfate and sodium chloride may contribute to water hardness or salinity but are not as prone to forming significant scale compared to calcium carbonate. Silica can form scale as well, but typically to a lesser extent and under different conditions than calcium carbonate.

Calcium carbonate is the principal scale-forming substance in water, particularly in the context of water treatment and distribution systems. The formation of scale primarily occurs when there is a change in conditions, such as temperature or pressure, that favors the precipitation of calcium carbonate from the water. This can happen when water becomes supersaturated with calcium ions and carbonate ions.

The tendency of water to form scale from calcium carbonate is significant because it can cause problems in pipes, boilers, and cooling systems, leading to reduced efficiency and potential damage. It is a common component of hard water, which can lead to scaling on surfaces, fixtures, and within plumbing systems.

Other substances listed, while they can also affect the quality of water or the scaling process, do not rank as the primary scale-forming compounds in standard water treatment contexts. For example, magnesium sulfate and sodium chloride may contribute to water hardness or salinity but are not as prone to forming significant scale compared to calcium carbonate. Silica can form scale as well, but typically to a lesser extent and under different conditions than calcium carbonate.