To determine the acid-conjugate base pair in the given reaction:
[tex]\[
HF + H_2O \rightarrow H_3O^+ + F^-
\][/tex]
we first need to understand the concept of an acid-conjugate base pair. According to the Brønsted-Lowry theory of acids and bases, an acid is a species that donates a proton (H^+) and a base is a species that accepts a proton. A conjugate base is what remains after the acid has donated its proton, and a conjugate acid is what forms when the base accepts a proton.
Let's breakdown the given reaction:
1. HF (hydrofluoric acid) donates a proton to the water molecule.
[tex]\[
HF \rightarrow F^- + H^+
\][/tex]
Hence, HF is acting as an acid, and F^- is its conjugate base since it is what remains after HF donates a proton.
2. H_2O (water) accepts a proton from HF.
[tex]\[
H_2O + H^+ \rightarrow H_3O^+
\][/tex]
Here, H_2O is acting as a base, and H_3O^+ (hydronium ion) is its conjugate acid since it is the result of H_2O accepting a proton.
Given these interactions:
- HF and F^- form an acid-conjugate base pair, as HF donates a proton becoming F^-.
- H_2O and H_3O^+ form a base-conjugate acid pair, as H_2O accepts a proton becoming H_3O^+.
Therefore, the correct acid-conjugate base pair in the reaction is:
[tex]\[
\boxed{\text{HF and } F^-}
\][/tex]
So, the correct choice is:
- HF and [tex]\( F^- \)[/tex].
