What is the conjugate base of ${\mathrm{HSO}}_4^{-}$?

No matter how negatively charged it is, it will never absorb a ${\mathrm{h}}^{+}$ to produce ${\mathrm{H}}_2{\mathrm{SO}}_4$ (Acid sulfuric) This is due to the fact that water totally dissociates sulfuric acid, which is a powerful acid.

In light of this, the sulphate ion $\left({\mathrm{SO}}_4^{2-}\right)$ is ${\mathrm{HSO}}_4^{-}$ conjugate base.