Mechanism of vanadium(V) oxidation of thallium(I) in aqueous acetic acid medium: A kinetic study

Abstract

The vanadium(V) oxidation of thallium(I) in aqueous acetic acid containing hydrochloric acid is considerably accelerated both by the hydrogen and chloride ions as well as by increasing acetic acid content of the medium. The experimental results obey the rate law:<br> <img src='http://www.niscair.res.in/jinfo/equation42.gif' border=0><br> where <i>β</i>₁,<i>β</i>₂ and <i>β</i>₃ are cumulative stability constants of the species TICI, TICI<img src='http://www.niscair.res.in/jinfo/two.gif' border=0>, TICl<img src='http://www.niscair.res.in/jinfo/three.gif' border=0> respectively, <i>k </i> is the rate constant of the slow step and <i>K</i>₁ is the equilibrium constant for,<br> H₄VO<img src='http://www.niscair.res.in/jinfo/plusfour.gif' border=0> + 2H⁺ <img src='http://www.niscair.res.in/jinfo/harpoon.gif' border=0> V(OH)<img src='http://www.niscair.res.in/jinfo/equation28.gif' border=0> + 2 H₂O<br> The main active species of vanadium(V) and thallium(I) are V(OH)<img src='http://www.niscair.res.in/jinfo/equation28.gif' border=0> and TICl<img src='http://www.niscair.res.in/jinfo/three.gif' border=0> respectively. The reaction constants involved in the mechanism are derived.