An empirical extension of the Debye-Hückel limiting activity equation is proposed. A survey of all the available data for electrolytes in water at 25° shows that the equation is in good agreement with the actual values of the mean ionic activity coefficient in dilute solutions, the average deviation being about 2% in 0.1 M-solution and proportionately less at lower concentrations.
The equation is applied to the activity data for zinc and cadmium sulphates, and dissociation constants are derived for these salts which agree with the values obtained from conductivity measurements. |