What is one chemical used to prevent scale in a boiler?

The correct answer is polymer, which is commonly used in boiler treatments to prevent scale formation. Scale consists of mineral deposits that accumulate on the heat exchange surfaces of the boiler, which can significantly reduce efficiency and lead to potential damage. Polymers serve as scale inhibitors by dispersing mineral particles, preventing them from adhering to surfaces.

They work by physically interfering with the crystallization process of minerals, making them more soluble in water and thus reducing the likelihood of scale formation. This helps maintain optimal thermal efficiency and prolongs the life of the boiler.

In contrast, sodium chloride is typically used for de-icing and water softening rather than scale prevention. Iron oxide is a type of corrosion product rather than a treatment for scale, while calcium carbonate is often a primary component of scale itself and does not prevent it.