A 25.00 mL sample of 1.00 M CH3CO2H is titrated with 1.00 M NaOH. Calculate the pH after 30.00 mL of NaOH has been added. (Ka = 1.8 x 10^-5) (a) 6.90 (b) 9.36 (c) 11.54 (d) 12.95

An acid-base titration is a quantitative analytical method used to determine the concentration of an acid or base in a solution. In this process, a solution of known concentration (the titrant) is added to a solution of unknown concentration until the reaction reaches its equivalence point, where the amount of acid equals the amount of base. The pH changes during the titration, and understanding this change is crucial for calculating the final pH.

Buffer solutions are mixtures that can resist changes in pH upon the addition of small amounts of acid or base. They typically consist of a weak acid and its conjugate base or a weak base and its conjugate acid. In the context of the titration of acetic acid (CH3CO2H) with NaOH, the solution will initially act as a buffer, maintaining a relatively stable pH until the equivalence point is approached.

The Henderson-Hasselbalch equation is a mathematical formula used to calculate the pH of a buffer solution. It relates the pH to the pKa of the weak acid and the ratio of the concentrations of the conjugate base to the weak acid. This equation is particularly useful in titration problems, as it allows for the determination of pH at various points in the titration process, especially before and after the equivalence point.