Arsenic acid, H₃AsO₄, is a polyprotic acid with 3 acidic protons. The equilibrium below shows the dissociation of the second acidic proton in water:

HAsO2−4(aq)+H3O+(aq)⟺H2AsO−4(aq)+H2O(l)HAsO42−(aq)+H3O+(aq)⟺H2AsO4−(aq)+H2O(l)

Identify the weaker acid then predict whether the equilibrium lies to the left or to the right.

Group of answer choices

HAsO2−4HAsO42−; left

H2AsO−4H2AsO4−; right

H3O+H3O+; right

Cannot be determined without K_a values.

H2OH2O; left