The function relating, at constant temperature and pressure, \(\mathit{\Gamma}_{i}^{\left(\text{n}\right)}\), \(\mathit{\Gamma}_{i}^{\left(\text{l}\right)}\) or \(\mathit{\Gamma}_{i}^{\left(\text{v}\right)}\), or the respective specific quantities \(\frac{n^{\text{l}}\ \Delta x_{i}^{\text{l}}}{m}\), \(\frac{A_{\text{s}}\ \mathit{\Gamma }_{i}^{\left(\text{l}\right)}}{m}\) or \(\frac{V^{\text{l}}\ \Delta c_{i}^{\text{l}}}{m}\) to the @A00296@ (or concentration) of component \(i\) in the equilibrium liquid phase. With solutions of more than two components such isotherms are unequivocal functions only when the ratios of the @M03980@ fractions (or concentrations) of all other components except \(i\) are kept constant. (\(A_{\text{s}}\) is the @A00430@, \(\mathit{\Gamma}_{i}^{\left(\text{n}\right)}\), \(\mathit{\Gamma}_{i}^{\left(\text{l}\right)}\), \(\mathit{\Gamma}_{i}^{\left(\text{v}\right)}\) are relative adsorptions, \(\Delta x_{i}^{\text{l}}\) is the change in @A00296@ of \(i\) resulting from bringing a specified mass \(m\) of solid into contact with a specified amount of solution \(n^{\text{l}}\), \(\Delta c_{i}^{\text{l}}\) is the change in concentration resulting from bringing a specified mass of solid into contact with a specified amount of solution of volume \(V^{\text{l}}\).)