The electrochemical-chemical (EC), electrochemical, chemical, electrochemical (ECE), and electrochemical, chemical, electrochemical-electrochemical, chemical, electrochemical (ECE-ECE) models with and without an included alpha variability were applied to the reduction of 2-methyl-2-nitropropane, benzenesulfonyl fluoride, and p-toluenesulfonyl fluoride. The three cases where alpha variability may occur are noted and discussed. It is shown that alpha variability, if present, may be of importance for ECE sequence in relation to k(f) determination.The presented cyclic voltammetry data obtained on glassy carbon electrode in the wide scan rate region were fully suitable for determination of kinetic parameters by estimation. (c) 2007 The Electrochemical Society.