# How do you determine conjugate acid and base pairs?

The conjugate base of any acid $H A$ simply the acid MINUS a proton, ${H}^{+}$; when we do this for $H A$ we get ${A}^{-}$. Likewise the conjugate acid of any base ${A}^{-}$ is simply the base plus a proton, ${H}^{+}$, to give $H A$. Mass and charge are conserved.
To use sulfuric acid as an example, we start with the ${H}_{2} S {O}_{4}$ formula; less a proton, this gives $H S {O}_{4}^{-}$ as the conjugate base, and the conjugate base of $\text{bisulfate}$ is $\text{sulfate}$ ion, $S {O}_{4}^{2 -}$. All I am doing is exchanging protons, ${H}^{+}$, and conserving mass and charge.
Can you tell the conjugate bases of the following acids: $H C l {O}_{4}$; ${H}_{3} P {O}_{4}$; $N {H}_{4}^{+}$; $N {H}_{3}$; $N {H}_{2}^{-}$; $H C \equiv C H$; $N {H}^{2 -}$?