Although the notions of structural identifiability and distinguishability are now well accepted in some domains of mathematical modeling such as econometrics, biology and pharmacokinetics, much remains to be done in others. The relevance of these notions to the building of phenomenological models in electrochemistry is illustrated by considering the Volmer-Heyrovsky reaction and three mechanisms for dissolution-passivation. It is shown that some classical methods for collecting data cannot ensure suitable identifiability and distinguishability properties. In some cases, simple modifications of the experimental procedure can remove these ambiguities. In others, one may resort to more recent techniques of investigation.