The following plot shows two pH titration curves, each representing the titration of 50.0 mL of 0.100 M acid with 0.100 M NaOH:

. (b) What is the approximate pH at the equivalence point for each of the acids?

Verified step by step guidance

1. Identify the equivalence point on each titration curve. This is the point where the curve shows a steep rise in pH, indicating that the amount of NaOH added is stoichiometrically equivalent to the amount of acid present.
2. For each curve, locate the volume of NaOH added at the equivalence point. This is typically where the curve is the steepest.
3. Determine the pH at the equivalence point for each curve by reading the pH value corresponding to the volume of NaOH added at the equivalence point.
4. Compare the pH values at the equivalence points for the two acids. Note that the pH at the equivalence point for a weak acid titrated with a strong base is typically greater than 7.
5. Record the approximate pH values at the equivalence points for each of the acids based on the graph.

Key Concepts

Titration

Titration is a quantitative analytical technique used to determine the concentration of an unknown solution by reacting it with a solution of known concentration. In this case, the titration involves a weak acid being neutralized by a strong base (NaOH), which results in a change in pH that can be plotted to visualize the reaction's progress.

Equivalence Point

The equivalence point in a titration is the stage at which the amount of titrant added is stoichiometrically equivalent to the amount of substance present in the sample solution. At this point, the reaction between the acid and base is complete, and the pH of the solution changes dramatically, often indicated by a steep slope in the titration curve.

pH of the Equivalence Point

The pH at the equivalence point varies depending on the strength of the acid and base involved in the titration. For a weak acid titrated with a strong base, the pH at the equivalence point will be greater than 7 due to the formation of a weak conjugate base, which can hydrolyze in water, resulting in a basic solution.