Final answer:
The pH will be basic at the equivalence point for a titration of a weak acid versus a strong base because the conjugate base of the weak acid remains in the solution, leading to a basic solution.
Step-by-step explanation:
The pH will be basic at the equivalence point in a titration of a weak acid versus a strong base. During this type of titration, the weak acid reacts with the strong base to form a salt and water. Since the weak acid does not dissociate completely, when it reacts with a strong base, the resulting solution is dominated by the conjugate base of the weak acid, which is typically a weak base and does not neutralize completely. This results in a solution that is basic at the equivalence point. Therefore, the correct answer to the question is c. weak acid vs. strong base.
In the case of a strong acid versus a strong base, the pH at the equivalence point would be neutral (pH = 7) since both the acid and base are strong and will neutralize each other completely. For a strong acid versus a weak base, we would expect the pH at the equivalence point to be acidic due to the weak base not being able to accept all the protons from the strong acid. Thus, these options are incorrect in the context of the question. Indicators such as phenolphthalein or thymol blue, which change color at pH greater than 7, are suitable for the titration of a weak acid due to the expected basic pH at the equivalence point.