# What is acid with two ionizable protons?

Apr 6, 2017

$\text{A diacid............}$

#### Explanation:

And the best example is $\text{sulfuric acid}$, which can donate two protons to aqueous solution:

${H}_{2} S {O}_{4} \left(a q\right) r i g h t \le f t h a r p \infty n s H S {O}_{4}^{-} + {H}_{3} {O}^{+}$

This equilibrium lies quantitatively to the right,

The second equilibrium, that which describes the acidity of $\text{bisulfate anion}$, lies to the right........

$H S {O}_{4}^{-} + {H}_{2} O r i g h t \le f t h a r p \infty n s S {O}_{4}^{2 -} + {H}_{3} {O}^{+}$

Overall:

${H}_{2} S {O}_{4} + 2 {H}_{2} O \rightarrow 2 {H}_{3} {O}^{+} + S {O}_{4}^{2 -}$.

We could find other diacids, but NONE as strong as $\text{sulfuric acid}$.