A student titrates 25.00 mL of an aqueous solution of a monoprotic weak acid HA with…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A student titrates 25.00 mL of an aqueous solution of a monoprotic weak acid HA with 0.150 M NaOH. The student collects the following data. (All volumes are cumulative volumes of NaOH delivered.)
Volume NaOH added (mL) → 0.00 5.00 9.00 12.00 16.00 17.50 18.25 20.00
Measured pH → 3.25 4.00 4.58 4.83 4.95 6.80 9.05 11.10
(a) Identify the equivalence volume and justify the choice.
(b) Calculate the initial molarity of the acid.
(c) Calculate Ka for the acid.
(d) Compute the percent error relative to the published value.
(e) Discuss the impact of ±0.02 pH uncertainty on the calculated Ka. No calculations are required.