An Investigation of the System Cr(III)/Cr(II) by Digital Polarography, at Different Cr(III) Concentrations, at Varying pH, and in Different Supporting Electrolytes

Author: Rathjen, Nancy Katherine

Year: 1969

Degree: Master's thesis

Advisor: Anson, Fred C.

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/N5V3-H153

Abstract

One of the implications of Marcus theory of electron transfer is that d, the electrochemical transfer coefficient, would not be constant, but would be a function of potential. Recent work has tended to confirm this implication.

To examine this possible potential-dependence d, the system Cr(III)/Cr(II) was investigated by digital polarography, at different Cr(III) concentrations, at varying pH, and in different supporting electrolytes. Most of the resulting rate data do suggest a potential-dependence of d.

Apparent heats of activation were obtained for three of the supporting electrolytes investigated, and from these a calculation was made of the magnitude of the potential-dependence predicted by Marcus theory. There was little correlation between the magnitude of the potential-dependence predicted by Marcus theory, and that actually found.

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