Indicator error. Consider the titration in Figure 10-2 in which the equivalence-point pH in Table 10-2 is 9.25 at a volume of 10.00 mL.

(a) Suppose you used the yellow-to-blue transition of thymol blue indicator to find the end point. According to Table 10-3, the last trace of green disappears near pH 9.6. What volume of base is required to reach pH 9.6? The difference between this volume and 10 mL is the indicator error.

(b) If you used cresol red, with a color change at pH 8.8, what would be the indicator error?

Figure 10-2

Table 10-2

Transcribed Image Text:

Buffer Excess region OH- 12 11 Maximum 10 Equivalence point slope (inflection point) Minimum slope (inflection point) 6. pH = pK, Ve/2 4 4 6 8. 10 12 14 16 V, (mL) 2. 7,