INDEX electroneutrality

In view of the term containing activity coefficients, the acidity function depends on the ionic type of the indicator. The definition of H0 is combined with the assumption that the ratio Yb/Ybh+ is constant for all indicators of the same charge type (in the present case the base is electroneutral hence the index 0 in //0). Thus, the acidity function does not depend on each individual indicator but on the series of indicators. 

The above expressions do not assume electroneutrality and simply represent an index change. Subsequent application of the electroneutrality conditions leads to a series of relationships between the fluctuating quantities,... 

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