Which option is NOT a purpose of polyphosphate addition in softening water?

Which option is NOT a purpose of polyphosphate addition in softening water?

• A. To Raise The pH
• B. To Prevent Recarbonation
• C. To Control Recarbonation
• D. To Prevent Excessively Heavy Calcium

Answer: (A)

The main idea is that polyphosphate in softening is used to keep hardness ions like calcium and magnesium in solution and prevent them from forming scale. By sequestering these ions, it reduces calcium carbonate or other mineral buildup on pipes and equipment and can aid corrosion control by helping form protective films on surfaces. Raising the pH is not an intended goal of adding polyphosphate; the dosing is not designed to push pH up. While polyphosphate can influence the water’s buffering to some extent, the purpose is not to raise pH. The other choices describe outcomes that are consistent with the role of polyphosphate in softening (preventing heavy calcium deposits and managing the carbonate system indirectly), whereas increasing pH is not a primary objective.

The main idea is that polyphosphate in softening is used to keep hardness ions like calcium and magnesium in solution and prevent them from forming scale. By sequestering these ions, it reduces calcium carbonate or other mineral buildup on pipes and equipment and can aid corrosion control by helping form protective films on surfaces. Raising the pH is not an intended goal of adding polyphosphate; the dosing is not designed to push pH up. While polyphosphate can influence the water’s buffering to some extent, the purpose is not to raise pH. The other choices describe outcomes that are consistent with the role of polyphosphate in softening (preventing heavy calcium deposits and managing the carbonate system indirectly), whereas increasing pH is not a primary objective.