A student titrates 25.00 mL of 0.100 M acetic acid ( , ) with 0.100 M sodium…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A student titrates 25.00 mL of 0.100 M acetic acid (CH3COOH, Ka=1.8×10−5) with 0.100 M sodium hydroxide at 25 °C. Assume volumes are additive.
(a) Calculate the base-dissociation constant Kb for the acetate ion.
(b) At the half-equivalence point, explain whether the proton-transfer reaction between acetate ion and water is considered reversible under titration conditions and identify the criteria you used for your assessment.
(c) During the very first incremental addition of NaOH, strong acid (H3O+) and strong base (OH−) react. Classify this neutralization step as reversible or irreversible in the context of the titration and defend your classification with chemical reasoning.
(d) Sketch the expected qualitative shape of the titration curve (pH versus volume of NaOH added) from 0 mL to 35 mL. On your sketch label regions where reversible proton-transfer equilibria dominate and regions where essentially irreversible reactions dominate, explaining the basis for each label.