The pH of 0.010 M H₃PO₄(aq) is 2.24; estimate the concentration of PO₄³^- in the solution.For H₃PO₄,The values of K_a1,K_a2,And K_a3 are 7.6 * 10^-³,
6.2 * 10^-⁸,And 2.1 * 10^-¹³,Respectively.

Question

Quizplus · Accepted Answer

The concentration of PO₄³⁻ is determined by the third dissociation constant (Kₐ3) of H₃PO₄, which is 2.1 * 10⁻¹³. Since the pH is 2.24, the concentration of H⁺ is much higher than the concentration of PO₄³⁻, making it approximately equal to Kₐ3 times the concentration of HPO₄²⁻, which is very low, resulting in a concentration of 2.3 * 10⁻¹⁸ M for PO₄³⁻.

The PH of 0