Which one of the following ion acts as chelating agent in HAP?*1 pointHydroxyl ionsPhosphate IonsCationsAll

The chelating agent in Hydroxyapatite (HAP) is Phosphate Ions. Here's why:

1. Hydroxyapatite is a naturally occurring mineral form of calcium apatite, its formula is Ca5(PO4)3(OH).

2. In this compound, the Phosphate Ions (PO4)3- have the ability to form multiple bonds with a single metal ion, making them a chelating agent.

3. Chelating agents are molecules that have multiple sites that can attach to a metal ion to form a ring-like structure. In the case of HAP, the Phosphate Ions can do this.

4. Hydroxyl ions and cations do not have this ability, and therefore do not act as chelating agents in HAP.

So, the answer is Phosphate Ions.