On the importance of bulk activity measurements for organic electrosorption studies

The importance of considering the bulk activities of both the organic compound and of the electrolyte is discussed for the case of organic electrosorption studies. The possible errors in the determination of the relative surface excess of the organic compound due to both of these factors separately and together are discussed. It is shown that the most serious errors due to either of these causes will occur in the region of organic concentrations in which the organic compound deviates negatively from Henry's law. Equations are derived which express these errors.