THE MEASUREMENT OF pH 



1X48-7 



PERCENT DISSOCIATION 



Fig. 1. — Ionization curves of some sulfonphthalein indicators, illustrating the 

 general relationships among the acid-base indicators and the applications of equation 5. 



Note: In some cases, the positions of the curves on the pH ordinate are approximate. 

 Table 2 should be consulted for accurate values of pK'. 



