Answer
\begin{matrix}
Base & Conjugate \space Acid \\
F^- & HF\\
C_2H_3{O_2}^- & HC_2H_3O_2\\
S{O_3}^{2-} & HS{O_3}^-\\
ClO^- & HClO
\end{matrix}
Work Step by Step
1. To find the conjugate base of an acid, just remove one proton $(H^+)$ from it.
- Remove a hydrogen, and subtract one from the charge.
$HC_2H_3O_2 \longrightarrow C_2H_3{O_2}^-$
$HS{O_3}^- \longrightarrow S{O_3}^{2-}$
2. To find the conjugate acid of a base, just add one proton $(H^+)$ to it.
- Add a hydrogen, and sum one to the charge.
$F^- \longrightarrow HF$
$ClO^- \longrightarrow HClO$