Final answer:
The titration problem in question seems to have an error regarding the use of NaCl for titration. The actual pH calculation during a titration depends on the specific weak acid and amount of strong base added, as well as the equilibrium reaction between them.
Step-by-step explanation:
The question pertains to acid-base titration, specifically calculating the pH during the titration of a weak acid with a strong base. There appears to be a confusion in the original question as NaCl is not used for titration purposes as it is a neutral salt and does not alter the pH of the acidic solution.
However, considering the typical scenario of titrating a weak acid with a strong base, we would use the provided example curves for titration of weak acids with NaOH. During the titration, the pH will gradually increase from the acidic pH as the base neutralizes the acid. If acetic acid (CH3CO2H) is the weak acid, the equivalence point would be around pH 8.72 according to Figure 14.18 and 11.3.1; but without the specific acid and titration curve data, an exact pH cannot be provided for the 25 mL mark. To calculate pH at a specific point during the titration, one would use the stoichiometry of the acid-base reaction and apply equilibrium constants to find the concentration of hydrogen ions and then calculate the pH.