Question

1. In the titration of a 25.00mL sample of 0.10M HAc (Ka=1.75x10-5) using 0.10M NaOH as the titrant, what is the pH at the following points during the titration? a). After the addition of 25.00mL NaOH?

Answer 1

At the equivalence point of titrating 25 mL of 0.10 M acetic acid with 25 mL of 0.10 M NaOH, the pH is 8.72 due to the formation of a basic acetate salt.

Therefore, after addition of 25.00 mL of 0.10 M NaOH to 0.10 M HAc, the pH will be 8.72.

Step-by-step explanation:

When 25.00 mL of 0.10 M NaOH is added to 25.00 mL of 0.10 M HAc (acetic acid), the reaction reaches the equivalence point. At this stage, all acetic acid has reacted with the sodium hydroxide to form water and acetate ions (CH3CO2−), and the solution contains only the acetate salt. The pH at equivalence point for a weak acid titrated with a strong base is above 7 due to the basic nature of the salt produced. To find the pH, use the information that at equivalence point, the titration curve of the acetic acid with NaOH has a pH of 8.72.

Therefore, after addition of 25.00 mL of 0.10 M NaOH to 0.10 M HAc, the pH will be 8.72.