The principle of complexometric titration is based on the formation of a stable complex between a metal ion and a ligand (a substance that can donate electron pairs).
In simple terms:
- A metal ion (analyte) reacts with a complexing agent (titrant) to form a colorless or stable complex.
- The titration continues until all the metal ions are bound by the ligand.
- An indicator is often used, which changes color when the last metal ion reacts, showing the end point.
Key Points:
- Most complexometric titrations use EDTA as the titrant because it binds strongly with metal ions.
- The amount of titrant used tells us the concentration of metal ions in the solution.
- Commonly used in water hardness determination, metal content in pharmaceuticals, and industrial analysis.
In short:
Complexometric titration works on the principle of metal ions forming a stable complex with a ligand, and the end point is detected by a color change with an indicator.