We have measured impedance spectra on Au(111) electrode in aqueous perchlorate solutions containing specifically adsorbing anions (SO42-, Cl-, Br- and I-) of about 10(-4) M concentrations at potentials where the dominant electrode process is the adsorption of the above anions. Accordingly. the impedance spectra have been analyzed in terms of the Frumkin-Melik-Gaykazyan adsorption impedance theory. With SO42-, Cl- we found the adsorption rates to be immeasurably high, with Br-and I- the apparent rate coefficients could be determined. For the halide anions this quantity increases in the order of Cl- > Br- > I-; and rapidly decreases with increasing electrode potential and coverage. We attribute this change to the decrease of the occupancy related hindrance factor overcompensates the increase of the rate coefficient.