Final answer:
The ratio of benzoate to benzoic acid at pH 7 is 1.
Step-by-step explanation:
The ratio of benzoate to benzoic acid at pH 7 can be determined using the Henderson-Hasselbalch equation. The Henderson-Hasselbalch equation is given by:
pH = pKa + log([A-]/[HA])
In this case, benzoate ion (A-) is the conjugate base and benzoic acid (HA) is the conjugate acid. At pH 7, the pH is equal to the pKa, so the ratio of [A-]/[HA] is 1. This means that the concentration of benzoate ion is equal to the concentration of benzoic acid.