Reaction of <i>cis</i>-diaqua nitrilotriacetatochromate(III) with L-ascorbic acid: A kinetic study

Abstract

The kinetics of the reaction of L-ascorbic acid (H₂A) with <i>cis</i>-[Cr(NTA)(H₂O)₂] has been studied over the range 0.02≤[H₂A]_T ≤ 0.1 mol dm^-3, 3.16 ≤ <i>p</i>H ≤ 4.64, 20.0 ≤ <i>t </i>≤ 35.0°C, 0.2 ≤ <i>I </i>≤ 1.0 mol dm^-3 (NaClO₄) and 10% ≤[MeOH] ≤ 50% (v/v). The rate of the reaction is found to increase with the increase in <i>p</i>H of the medium. The reaction is hardly affected by change in ionic strength and dielectric constant of the medium. Activation parameters, Δ<i>H</i>^#<i> </i>and Δ<i>S</i>^#have been found to be 39.4, 34.1, 102.0 kJ mol^-1 and -168.00±0.15, -208.0±0.35, 53.0±1.4 J K^-1 mol^-1 for <i>k</i>₁, <i>k-</i>₁ and <i>k</i>₂ path respectively. Anation of <i>cis</i>-[Cr(NTA)(H₂O)₂] and [Cr(NTA) (OH₂)(OH)]^- follow Ia and Id path respectively.