Oxidation of Co(II) EDTA complex by V(V) under the conditions where VO₂⁺ and decavanadates coexist

Abstract

The oxidation of Co(II) EDTA complex by V(V) in the <i style="mso-bidi-font-style: normal">p</i>H range 3.05-4.27 obeys first order kinetics each with respect to vanadium (V) and the complex. The dependence of rate on [H^+] is complex. In this <i style="mso-bidi-font-style: normal">p</i>H range, V(V) is present in the form of VO₂⁺ and decavanadates, HV ₁₀O₂₈^5-, and H₂V₁₀O₂₈^4-, the latter being predominant. The kinetic results show that the rate is almost exclusively determined by paths involving HV₁₀O₂₈^5- and H₂V₁₀O₂₈^4- , the latter being about 9 times more reactive than the former.