The interest of checking structural properties of reaction mechanisms prior to any attempt at estimating their kinetic parameters is illustrated by considering the identifiability of the parameters of the Volmer-Heyrovsky mechanism. The technique employed applies to any of the small-signal methods used for the study of electrochemical mechanisms, as well as to signals involving large deviations. It turns out that steady-state measurements, electrochemical impedance spectroscopy and linear sweep voltammetry do not make it possible to estimate the kinetic parameters unambiguously, even from noise-free data, contrary to electrogravimetry. This type of analysis, which seems still largely ignored among electrochemists, can be used for the choice of experimental procedures to be employed.