Cyclic voltammetry, impedance and chronocoulometry have been employed for quantitative study of n-propanol (n-PA) adsorption at the bismuth single-crystal plane\aqueous Na2SO4 solution interface. The adsorption characteristics of n-PA, obtained from the impedance and chronocoulometric measurements, are in good agreement within the limits of surface charge densities -16 < sigma < 10 mu C cm(-2). The adsorption characteristics (Gibbs energy of adsorption -Delta G(A)(0); limiting Gibbs adsorption Gamma(max); limiting potential shift of zero charge E-N; molecular interaction parameter a, etc.) of n-PA depend on the crystallographic structure of the electrode surface. Comparison of the adsorption parameters for n-PA, n-butanol (n-BA), isobutanol (iso-BA), sec-butanol (sec-BA), tert-butanol (tert-BA), butylacetate (BAG) and cyclohexanol (CH) shows that the adsorption activity and other parameters depend on the length and structure of hydrocarbon radical of the organic compound studied. The adsorption activity of n-PA rises in the order of Bi planes (111)<(001)<(01(1) over bar). The difference between the adsorption activities of various Bi planes decreases as the adsorption activity of the organic compound at the metal\solution interface decreases in the order of adsorbates BAC > CH > n-BA > n-PA. The molecular interaction parameter a decreases in order of planes (001) greater than or equal to (111) > 01(1) over bar as the reticular density of planes increases, and in order of adsorbates n-PA < n-BA < CH as the molar volume of adsorbate rises. The limiting Gibbs adsorption Gamma(max) increases in order of planes (01(1) over bar) < (111) < (001) as the superficial density of planes decreases. Very low Gamma(max) and E-N values for Bi(01(1) over bar) plane indicate that n-PA molecules probably have a flat orientation on the chemically most active Bi(01(1) over bar) single-crystal plane in the region of maximum adsorption.