Complexometric titration is a type of titration used to determine the concentration of metal ions in a solution. It involves the formation of a stable complex between the metal ions and a chelating agent, such as EDTA (ethylenediaminetetraacetic acid). The endpoint of the titration is often indicated by a color change, which occurs when all the metal ions have reacted with the chelating agent. During the titration, a solution containing the metal ions is mixed with the chelating agent. As the titration progresses, the chelating agent binds to the metal ions, forming a complex. The amount of chelating agent required to reach the endpoint allows for the calculation of the concentration of the metal ions in the original solution.