It is a complex salt which is used to soften hard water.
The chemical name of Calgon is hexametaphosphate.
The chemical formula of Calgon is .
Process:
In this process, when Calgon is added to hard water, it causes the magnesium and calcium ions present in hard water to displace sodium ions from the anion complex of Calgon.
It means a complex anion is formed when Calgon ionizes.
The chemical reaction is as follows:
It results in the elimination of magnesium and calcium ions from hard water with Calgon.
When water is softened then sodium ions are released in the water.