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,black spheres represent oxygen atoms,and shaded spheres represent A^- ions.(K⁺,H₃O⁺initially present,OH^-initially present and solvent water molecules have been omitted for clarity. )
-Which picture represents the equilibrium state of the solution after addition of one H₃O⁺ ion to the solution shown in picture (1) ?

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,black spheres represent oxygen atoms,and shaded spheres represent A^- ions.(K⁺,H₃O⁺initially present,OH^-initially present and solvent water 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,black spheres represent oxygen atoms,and shaded spheres represent A<sup>-</sup> ions.(K<sup>+</sup>,H<sub>3</sub>O<sup>+ </sup>initially present,OH<sup>- </sup>initially present and solvent water molecules have been omitted for clarity. ) -Which picture represents the equilibrium state of the solution after addition of one H<sub>3</sub>O<sup>+</sup> ion to the solution shown in picture (1) ? A) (2) B) (3) C) (4) D) (5)

-Which picture represents the equilibrium state of the solution after addition of one H₃O⁺ ion to the solution shown in picture (1) ?

Quizplus · Accepted Answer

When a H₃O⁺ ion is added to the solution, it will react with the KA salt to form more HA and KH₃O, shifting the equilibrium to the left. As a result, the concentration of KA will decrease and the concentration of HA and KH₃O will increase. Picture (4) represents this new equilibrium state with more HA and KH₃O and less KA.

The Following Pictures Represent Solutions That Contain a Weak Acid