The electrochemical interface between polycrystalline silver and alkaline NaF/NaOH electrolytes at various pH values has been studied by means of cyclic voltammetry and ac-impedance spectroscopy. Hydroxide electrochemisorption has been observed in a wide potential range (between -1.1 and 0 V SCE depending upon pH). Study of the hydrogen peroxide reduction at silver rotating-disc electrodes in alkaline NaF/NaOH electrolytes has proved the existence of a slow chemical step in the reaction mechanism, its rate being strongly affected by the submonolayer surface oxidation. The reaction scheme is proposed for the hydrogen peroxide reduction, which takes into consideration the structure of the adsorbate layer at the electrode;electrolyte interface at the variable potential.