The unusual property of EDTA is its ability to chelate or complex metal ions in 1:1 metal-to-EDTA complexes. The fully deprotonated form (all acidic hydrogens removed) of EDTA binds to the metal ion. ... Many of the reactions are pH dependent, especially the weaker forming complexes with Ca+2 or Mg+2.
Why are EDTA titrations pH dependent?
Dependency on pH
The strength and stability of EDTA complexes depends mainly on the pH. The number of electron pairs actually available to form coordination bonds depends on the dissociation levels of the acid groups and therefore the pH.
Does EDTA change the pH?
EDTA (acid) is almost insoluble in water. ... First, dissolve EDTA-2Na then adjust the pH. The range of pH in this application is + _ 0.2, so don't worry about the exact 8.0 pH.
