Is sulfuric acid a diprotic acid?

1 Answer
Apr 19, 2017

"Sulfuric acid"Sulfuric acid is a diprotic reagent.......

Explanation:

The conjugate base of sulfuric acid is bisulfate ion, HSO_4^(-)HSO4, which itself is a strongish Bronsted acid:

H_2SO_4(l) + H_2O(l) rarr HSO_4^(-) + H_3O^+H2SO4(l)+H2O(l)HSO4+H3O+

And HSO_4^(-) + H_2O(l) rarr H_3O^+ + SO_4^(2-)HSO4+H2O(l)H3O++SO24

Overall,

H_2SO_4(aq) + 2H_2O rarr 2H_3O^+ + SO_4^(2-)H2SO4(aq)+2H2O2H3O++SO24

You will have to look up the K_aKa for HSO_4^(-)HSO4, but we generally assume that sulfuric acid is diprotic in aqueous solution.