Kinetics of oxidation of thiocyanate ion by manganese(III) in pyrophosphate medium

✍ Scribed by Ishwar K. Bhat; Bailure S. Sherigara; Ivan Pinto

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 415 KB
• Volume: 18
• Category: Article
• ISSN: 0340-4285
• DOI: 10.1007/bf00139948

✦ Synopsis

Mn m is stabilized by pyrophosphate in weakly acidic solutions. The nature of the complex formed was elucidated spectrophotometrically. The kinetics of Mn m oxidation of thiocyanate in pyrophosphate medium was investigated over the pH range 2-3. The oxidation followed first order kinetics with [Mnm]. The effects of varying [Mn'H], [NCS-], added Mn" and metal ions, pH, total [P2Ov 4-] and added C10~, C1-and SO 2-were studied. The order in [NCS-] was unity, and increasing [H +] increased the rate. Retardations with added P20~ -and Mn" were observed. Complexation of NCS-as KEZn(NCS)r decreased the reactivity without any change in overall mechanism. The dependence of the reaction rate on temperature was examined, and activation parameters were computed from Arrhenius and Eyring plots. A mechanism consistent with the results is proposed.