The most important example of hexadentate Ligand is EDTA(ethylenediaminetetraace
ID: 699528 • Letter: T
Question
The most important example of hexadentate Ligand is EDTA(ethylenediaminetetraacetato) Complexation with EDTA should make it more difficult to reduce the ion to the metal form,compared to the aqua ions.That is the free energy of [M(EDTA)]2- will be lower than that of [M(H2O)6]2+ and hence it should take a greater amount of added energy to raise the system to the energy of the elemental metal.Since EDTA4- bonds to a metal ion through six donor atoms,it forms highly stable complexes and in general it is used to hold metal ions in solution.EDTA4- Ligand is used to trap metal ions such as Mg2+ and Ca2+ ions in hard water.
EDTA forms an octahedral complex with most M2+ cations in aqueous solution.The main reason that EDTA is used so extensively in the standardization of metal cation solutions is that the formation constant for most metal cation EDTA complexes is very high.
Explanation / Answer
The ligand edta forms stable complexes with hard acid centres. How will complexation with edta affect the reduction of M 2+ to the metal in the 3d series?