HF(aq) + H₂O(l) ⇄ H₃O⁺(aq) + F⁻(aq) Ka = 6.3 x 10⁻⁴ at 25°C
The acid ionization equilibrium for HF is represented by the chemical equation above. A student claims that the pH of a solution that contains 0.100M HF(aq) and 0.100MNaF(aq) will change only slightly when small amounts of acids or bases are added. Which of the following pairs of equations can the student use to justify the claim?
a) HF(aq) + OH⁻(aq) → H₂O(l) + F⁻(aq) and OH⁻(aq) + H₃O⁺(aq) → 2 H₂O(l)
b) H₃O⁺(aq) + OH⁻(aq) → 2 H₂O(l) and F⁻(aq) + H₃O⁺(aq) → HF(aq) + H₂O(l)
с) HF(aq) + OH⁻(aq) → H₂O(l) + F⁻(aq) and F⁻(aq) + H₂O(l) → HF(aq) + OH⁻(aq)
d) HF(aq) + OH⁻(aq) → H₂O(l) + F⁻(aq) and F⁻(aq) + H₃O⁺(aq) → HF(aq) + H₂O(l)
