How do chelates work in boiler systems?

Chelates play a vital role in boiler systems primarily by binding to scale-forming ions and keeping them in solution, making option B the correct choice. This is crucial for the prevention of scale buildup within the boiler. In the presence of chelating agents, metal ions that typically contribute to scaling—such as calcium and magnesium—form stable complexes with these agents instead of precipitating out of the water and forming hard deposits. This helps maintain the efficiency and longevity of boiler systems, as scale can lead to overheating, reduced heat transfer, and potentially serious damage to the equipment.

The other options do not accurately represent the function of chelates in boiler systems. For instance, while evaporating and condensing with steam is a process associated with some substances in the boiler, it does not pertain to the fundamental action of chelates. Creating a slippery layer relates more to the functionality of lubricants rather than the scale management role of chelating agents. Lastly, generating heat during a chemical reaction is not applicable to the action of chelates within a boiler system; instead, their purpose is to keep ions in solution, preventing scale formation without a direct heat-generating reaction.