Is sulfuric acid a diprotic acid?

1 Answer
Apr 19, 2017

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

Explanation:

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

H_2SO_4(l) + H_2O(l) rarr HSO_4^(-) + H_3O^+

And HSO_4^(-) + H_2O(l) rarr H_3O^+ + SO_4^(2-)

Overall,

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

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