Determination of Ion Interaction Parameters from Activity and Osmotic Coefficient Data

Determination of Ion Interaction Parameters from Activity and Osmotic Coefficient Data 

OH )) are equal to -(0.050 0.003) kgmol and 0.021 0.003 kg mol , respectively. These can be compared with the same differences obtained from ion interaction parameter values determined from the ionic strength dependence of the protolysis constant of water in NaCl and KCl media (see Table 5.5). These latter values are (ei(Na+, OH-)-ei(K+, OH )) = (0.103 0.012 - 0.152 0.011) = -(0.049 0.016) kgmol-i and ( 2( 4+, OH-)- 2(K. OH )) = (0.062 0.019 - 0.015 0.020) = 0.047 0.028 kg mol . The 95% confidence intervals of the latter values overlap the former values, and consequently, the hypothesis that they are similar cannot be rejected. Therefore, the values for (K, OH ) and 2(K OH ) determined from the activity and osmotic coefficient data of Robinson and Stokes (1959) will be used as the starting point for the calculation of the ion interaction parameters. 

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