Kinetics and Mechanism of Oxidation of Chromium (III) – [2-(Phenyl Amino) Acetohydrazide] by Periodate.
Ahmed A Abdel- Khalek1, Berry Abd-El Ghani Sabrah2, Yasser Abdel Rhman3
1Ahmed A Abdel-Khalek, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef City, Egypt.
2Berry Abd-El Ghani Sabrah, Chemistry Department, Fayoum University, Faculty of Science, Fayoum City, Egypt.
3Yasser Abdel Rahman, Chemistry Department, Fayoum University, Faculty of Science, Fayoum City, Egypt.
Manuscript Received on December 04, 2015. | Revised Manuscript Received on December 15, 2015. | Manuscript published on December 20, 2015. | PP: 5-10 | Volume-3 Issue-12, December 2015. | Retrieval Number: L06751231215/2015©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Oxidation of [Cr(HL)(H2O)4 ] 3+ (where HL = 2-(phenylamino) acetohydrazide ligand) by periodate was studied spectrophotometrically in aqueous solution over varying ranges of pH, ionic strength ,temperature, complex concentration (2.0 – 6.0)×10-4mol dm-3 and periodate (1.0 – 4.5)×10-2 mol dm-3 . The reaction is first order with respect to [H5IO6 ] and [CrIII]. The rate of reaction increases with increasing of temperature and pH over the study range (1.59-2.62). The rate of the reaction is independent on the complex concentration and decreases with ionic strength. Oxidation of [Cr(HL)(H2O)4 ] 3+ follows the rate law, d[CrVI] / d t =(k2 + k3 / [H+ ]) [H5IO6 ] [Cr(HL)(H2O)4 3+] . Where, k obs. = (k 2 + k 3 / [H+ ]) [H5IO6 ]. The thermodynamics activation parameters involving ∆H*and ∆S* have been calculated in excited state.
Keywords: Periodate, oxidation, acetohydrazide.