Аннотация:Electrocapillary curves were measured in 1 N Na//2SO//4 plus 1. 74 N H//2SO//4 plus x N SnSO//4 plus y M HCO solutions, where x equals 0, 0. 02, 0. 06, 0. 1, 0. 15, and 0. 2, and y equals 0, 0. 1, and 2. 0. The attraction constant and the adsorption equilibrium constant were calculated as functions of the potential in the range from 0 to minus 0. 4 V from experimental data in accordance with the Frumkin isotherm. It is postulated that in this range of potentials divalent tin is adsorbed on a mercury surface in the form of neutral complexes of the type Sn left bracket Sn(SO//4)//2 right bracket . A comparison of the results obtained in the presence and absence of formaldehyde showed that the latter enhances the solvation of the tin complexes in the solution and thereby lowers their surface activity.