The following pictures represent solutions that contain a weak acid HA (pK_a = 5.0) and 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 of these solutions is pH = pK_a?

Question

The following pictures represent solutions that contain a weak acid HA (pK_a = 5.0) and 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. )

The following pictures represent solutions that contain a weak acid HA (pK<sub>a</sub> = 5.0) and its potassium salt KA.Unshaded spheres represent H atoms and shaded spheres represent A<sup>-</sup> ions.(K<sup>+</sup>,H<sub>3</sub>O<sup>+</sup>,OH<sup>-</sup>,and solvent H<sub>2</sub>O molecules have been omitted for clarity. ) -For which of these solutions is pH = pK<sub>a</sub>? A) All have pH = pK<sub>a</sub>. B) (1) , (2) and (3) C) (1) and (4) D) (2) and (3)

-For which of these solutions is pH = pK_a?

Quizplus · Accepted Answer

pH = pK_a when [HA] = [A^-]. This is the case for (1) and (4).

The Following Pictures Represent Solutions That Contain a Weak Acid