What is the second stepwise equilibrium constant expression for phosphoric acid H₃PO₄? A)K_a2 = ([H₃O⁺][H₂PO₄^-])/([H₃PO₄]) B)K_a2 = ([H₃O⁺]2[HPO₄^2-])/([H₃PO₄]) C)K_a2 = ([H₃O⁺]3[PO₄^3-])/([H₃PO₄]) D)K_a2 = ([H₃O⁺][HPO₄^2-])/([H₂PO₄^-])

Question

Quizplus · Accepted Answer

The second stepwise equilibrium for phosphoric acid involves the dissociation of the hydrogen phosphate ion (HPO4^2-) into the phosphate ion (PO4^3-) and a hydrogen ion (H+). The correct expression includes the concentrations of the products (H+ and PO4^3-) divided by the concentration of the reactant (HPO4^2-), which matches choice D.

What Is the Second Stepwise Equilibrium Constant Expression for Phosphoric