Titration merging curves

The different titrations curves are extrapolated to pK=3.6. From Figure 7, it appears that for both acetone-water mixtures containing respectively 42% and 50% of acetone, the curves superimpose in the whole range of ionization this already justifies their use as correct reference curves. Moreover, viscosity measurements show also that conformational transition no more exists in such mixtures. For high a, the curves also merge into a single one except for water and acetone-water (12%) where it can be admitted that the transition is not completed at a=1. 

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