Impedance technique is used for studying the time effects observed in the ideal polarizability region on renewable tin-lead alloy electrodes in 0.3 mol 1(-1) NaF solution. These effects are shown to be caused by a nonfaradaic process of the enrichment of electrode surface by lead atoms, the latter being the surface-active component of the alloy. On the basis of the results on the charge impact on the kinetics of alloy's surface-composition variation, the method of elucidating the relative position of 'electrocapillary curves' of solid (here, lead and tin) electrodes is put forward.