# What is the conjugate acid of HPO2^2-?

Dec 12, 2015

${\text{H"_2"PO}}_{2}^{-}$

#### Explanation:

If we can find the conjugate acid of ${\text{HPO}}_{2}^{2 -}$, then ${\text{HPO}}_{2}^{2 -}$ itself is a base.

Since it has a negative charge, it must lack a positive charge, i.e. it lacks a proton. Therefore, it wants to act as a Bronsted base.

If the molecule is a Bronsted base, then it can accept a proton $\left({\text{H}}^{+}\right)$.

Thus, if we add a hydrogen ion (a proton) to the ion, we get ${\text{H"_2"PO}}_{2}^{-}$.