Final answer:
In base hydrolysis of a fluoride ion in water, fluoride acts as the Brønsted-Lowry base, water as the acid, and the reaction produces the conjugate acid HF and the conjugate base OH⁻ leading to a slightly basic solution.
Step-by-step explanation:
For the base hydrolysis reaction of a fluoride ion in water, the species can be labeled according to the Brønsted-Lowry acid-base theory. The fluoride ion (F⁻) is acting as a weak Brønsted-Lowry base as it accepts a proton from water, which is acting as the Brønsted-Lowry acid in this context. When fluoride reacts with water, the reaction can be represented as F⁻ (aq) + H₂O (l) ≈ HF (aq) + OH⁻ (aq). In this reaction, water (H₂O) donates a proton to the fluoride ion and thus serves as the Brønsted-Lowry acid, and its conjugate base is the hydroxide ion (OH⁻). The fluoride ion (F⁻), after accepting a proton, forms hydrofluoric acid (HF) and is the conjugate acid. The production of hydroxide ions results in a solution that is slightly basic due to salt hydrolysis.