The variations in the reduction potential when 100 ml of 0.1N Fe2+ is titrated against 0.1N Ce4+ are tabulated in the following table (Table 24.1).
By plotting the potential against volume of Ce4+ added, Figure 24.1 is obtained. The equivalence point corresponds to the point of inflection of the curve. A better procedure to obtain the equivalence point is to make use of the fact that the slope of E/V is large in the vicinity of the equivalence point. If E/V is plotted against V (Figure 24.2), the sharp maximum corresponds to the equivalence point.
Figure 24.1 : A potentiometric titration curve.
Figure 24.2 : Determination of the equivalence point in a potentiometric titration
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