$H C l+H_{2} O \rightleftharpoons H_{3} O^{+}+C l^{-}$

$\mathrm{Cl}^{-}$ is conjugate base of $\mathrm{HCl} \& \mathrm{H}_{3} \mathrm{O}^{+}$ is conjugate acid of $\mathrm{H}_{2} \mathrm{O}$

Stronger acids has weaker conjugate base aciding order:

$R C O O H>H C \equiv C H>N H_{3}>R H$

So basicity order : $R C O O^{-}  < H C \equiv C^{-} < N H_{2}^{-} < R^{-}$