Assessment of linearity between steady-state limiting current and analytical concentration of weak acids in the reaction of hydrogen evolution

The reaction of hydrogen evolution from the acids: hydrochloric, hydrogen sulfate ion, monochloroacetic and lactic have been studied by steady-state voltammetry at platinum microdisc electrodes. From the experimental voltammetric parameters, such as half-wave potential, (E(1/4)-E(3/4)) values and steady-state limiting current, it has been ascertained that the second order CE mechanism, involved in the discharge of protons arising from the weak acids investigated, is characterized by a chemical reaction which is fast over the whole concentration range explored. Theoretical calibration plots have been examined in the concentration range 1x10(-6)-1x10(-1) M and the zone over which linearity exists has been verified both from a theoretical and experimental point of view.