The following pictures represent solutions that contain a weak acid HA and/or its potassium salt KA.Unshaded spheres represent H atoms and shaded spheres represent A^- ions.(K⁺,H₃O⁺,OH^-,and solvent H₂O molecules have been omitted for clarity. )
-For which solution(s) is pH = pK_a?

Question

The following pictures represent solutions that contain a weak acid HA and/or its potassium salt KA.Unshaded spheres represent H atoms and shaded spheres represent A^- ions.(K⁺,H₃O⁺,OH^-,and solvent H₂O molecules have been omitted for clarity. )

-For which solution(s) is pH = pK_a?

Quizplus · Accepted Answer

The pH equals pKa (or pKs in this context) at the midpoint of a titration of a weak acid or base, where the concentrations of the acid and its conjugate base are equal. This condition can occur in multiple solutions if they represent such midpoints for their respective weak acids or bases.

The Following Pictures Represent Solutions That Contain a Weak Acid