## Chemistry (7th Edition)

- The second solution (2) has the highest pH; - The first solution has the greater $HF$ dissociation;
- The presence of $F^-$ ions in the second solution makes its pH greater than the pure $HF$ one, because the fluoride ion can act as a base. - Due to the common ion effect, the presence of $F^-$ in the second solution restricts the dissociation of $HF$, because it moves the equilibrium to the left side: $HF(aq) + H_2O(l) \lt -- \gt F^-(aq) + H_3O^+(aq)$ Therefore, the first solution has the greater $HF$ percent dissociation.