What can be used to control scaling, but can never be used to control corrosion?

Sequestering agents are compounds that can bind to metal ions in water, forming stable complexes. These agents are effective at controlling scaling because they prevent the precipitation of mineral deposits, such as calcium and magnesium salts, by keeping these ions in solution and away from surfaces where scale would typically form. By doing so, they help maintain the efficiency of water distribution systems and reduce maintenance issues associated with scale buildup.

However, sequestering agents do not have properties that address the electrochemical reactions responsible for corrosion. Corrosion inhibitors are specifically designed to mitigate the corrosion process by forming protective films on metal surfaces or altering the electrochemical environment. Since sequestering agents are focused solely on managing scaling through ion binding, they cannot contribute to the prevention or reduction of corrosion, making them ineffective for that purpose.

This distinct function of sequestering agents highlights their role in controlling scaling while simultaneously illustrating their limitation concerning corrosion control.