Final answer:
The equivalence point on the titration curve is where the pH is 7. The pH at the midpoint is equal to the pKa or pK of the weak acid or weak base. Before the equivalence point, the gradual increase in pH is due to the partial ionization of the weak acid. After the equivalence point, the behavior of the weak acid depends on its conjugate base.
Step-by-step explanation:
a. The equivalence point on the titration curve can be identified as the point on the curve where the pH is equal to 7. In a titration of a strong acid with a strong base, the equivalence point always occurs at pH 7.
b. The pH of the solution at the halfway point of the titration, also known as the midpoint, is equal to the pKa of the weak acid or pK of the weak base. This is because at the midpoint, the concentrations of both acid and conjugate base (or base and conjugate acid) are equal.
c. The shape of the curve before the equivalence point is determined by the gradual increase in pH as more base is added to the weak acid. This is due to the partial ionization of the weak acid, which results in a slower change in pH compared to the steep rise in pH seen after the equivalence point.
d. After passing the equivalence point, the behavior of the weak acid depends on its conjugate base. If the conjugate base is a strong acid, it will continue to react with water, forming hydronium ions and resulting in a decrease in pH. If the conjugate base is a weak acid, it will not react significantly with water, resulting in a relatively constant pH.