Final answer:
In the reaction HF + H₂O ↔ F⁻ + H₃O⁺, HF is the acid and H₂O is the base; F⁻ is the conjugate base and H₃O⁺ is the conjugate acid. Equilibrium favors the formation of the weaker acid and base, so it lies predominantly to the right.
Step-by-step explanation:
In the reaction HF + H₂O ↔ F⁻ + H₃O⁺, hydrofluoric acid (HF) is acting as the acid and water (H₂O) is acting as the base according to the Brønsted-Lowry definition. When HF donates a proton, it forms its conjugate base, fluoride ion (F⁻), and when H₂O accepts a proton, it forms its conjugate acid, hydronium ion (H₃O⁺). Given that HF is a weak acid and F⁻ is a weak base, the equilibrium in this reaction tends to favor the side with the weaker acid and base. Therefore, the equilibrium lies predominantly to the right, as hydrofluoric acid is weaker than hydronium, and the fluoride ion is a weaker base compared to water.