CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A laboratory has 250mL of 0.100M CH₃COOH(aq) (Ka=1.8×10−5) at 25∘C. A buret containing 0.100M NaOH(aq) is used to titrate the acetic acid solution. Volumes are additive, and temperature changes are negligible.
(a) Derive an algebraic expression, in terms of the added volume V (in liters) of the NaOH solution, for the concentrations of CH₃COOH and CH₃COO⁻ present after partial neutralization but before the equivalence point.
(b) Using your expression from part (a), determine the range of V for which both CH₃COOH and CH₃COO⁻ concentrations remain at least 1.0% of their initial respective maximum values. Show all reasoning.
(c) Explain why the range you obtained in part (b) delineates the interval over which the solution acts as an effective buffer.