The pH-Dependent Metal-EDTA Equilibrium

At this point in the chapter, those who want to spend more time on instrumental methods of analysis might want to move to a new chapter. We now consider equilibrium calculations required to understand the shape of an EDTA titration curve. 

Equation 13-1 does not Imply that is the only species that reacts with It only says that the equilibrium constant is expressed in terms of the concentration of Y . 

The product [EDTA] accounts for the fact that only some free EDTA is in the form Y . 

If the pH is fixed by a buffer, then ay4- is a constant that can be combined with Kf. 

K (= ay4- Lf) is called the conditional formation constant or the effective formation 

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