Answer
$OCl^-$ is the stronger base.
Work Step by Step
The stronger the acid, the weaker will be its conjugate base.
Judging by their $K_a$ values, acetic acid is the stronger of the pair.
$1.8 \times 10^{-5} \gt 3.5 \times 10^{-8}$
- $OCl^-$ is the conjugate base of hypochloric acid.
- $C_2H_3O_2^-$ is the conjugate base of acetic acid.
Therefore, $C_2H_3O_2^-$ is the weaker base, and $OCl^- $ is the stronger one.
