The following data were recorded during the titration of 25.0 mL of a monoprotic weak…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
The following data were recorded during the titration of 25.0 mL of a monoprotic weak acid with 0.100 M NaOH at 25 °C. Each pH value was measured after thorough mixing.
Volume NaOH added (mL) | pH
0.00 | 3.00
5.00 | 3.70
10.00 | 4.35
12.50 | 4.74
20.00 | 6.97
22.50 | 8.25
25.00 | 8.90
27.50 | 11.36
Use the tabulated data to answer the questions that follow.
(a) Determine the volume of NaOH that corresponds to the equivalence point, and explain how you arrived at your answer using the data provided.
(b) Using an appropriate data point, calculate the numerical value of pKa for the acid and report Ka.
(c) Calculate the initial molarity of the weak acid present in the 25.0 mL sample.
(d) Predict the principal species (major ionic or molecular form) present in solution at 27.50 mL of NaOH added, and justify your prediction.