A 1.0 L aqueous solution contains equimolar amounts of hydrofluoric acid (HF) and…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A 1.0 L aqueous solution contains equimolar amounts of hydrofluoric acid (HF) and sodium fluoride (NaF) at 25 °C.
Answer the following questions about the behavior of this solution when small amounts of strong base are introduced.
(a) Identify the conjugate acid–base pair present in the solution.
(b) Describe, at the particulate level, the sequence of events that occurs immediately after a small quantity of solid NaOH is dissolved in the buffered solution.
(c) Using equilibrium reasoning, explain why the pH of the solution changes only slightly after the addition described in part (b). Emphasize the role of Le Châtelier’s principle in your explanation.