Question

What is Calgon process in chemistry?

Answer 1

Calgon:

• 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 $({\mathrm{NaPO}}_3{)}_6$.

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:

$$\begin{gathered} 2{\mathrm{CaCl}}_2\left(\mathrm{aq}\right)+{\mathrm{Na}}_2\left[{\mathrm{Na}}_4\right({\mathrm{PO}}_3{)}_6\left]\right(\mathrm{s})\to {\mathrm{Na}}_2[{\mathrm{Ca}}_2\left({\mathrm{PO}}_3{)}_6\right]\left(\mathrm{aq}\right)+4\mathrm{NaCl}\left(\mathrm{aq}\right) \\ 2{\mathrm{MgSO}}_4\left(\mathrm{aq}\right)+{\mathrm{Na}}_2\left[{\mathrm{Na}}_4\right({\mathrm{PO}}_3{)}_6\left]\right(\mathrm{s})\to {\mathrm{Na}}_2[{\mathrm{Mg}}_2\left({\mathrm{PO}}_3{)}_6\right]\left(\mathrm{aq}\right)+2{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right) \end{gathered}$$

• 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.