For a generic salt derived from a weak acid () and a weak base (), which of the following mechanisms — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

In WA-WB salts, neither ion is a stable spectator; both hydrolyze. The combined mechanism is the simultaneous reaction of $B^+$ (yielding $H^+$) and $A^-$ (yielding $OH^-$), summarized as $B^+ + A^- + H_2O \rightleftharpoons BOH + HA$. The equilibrium constant for this combined process is mathematically derived as $K_h = \frac{K_w}{K_a \cdot K_b}$. Because the concentration terms cancel out during derivation, the pH of the solution ($pH = 7 + \frac{1}{2}pK_a - \frac{1}{2}pK_b$) is entirely independent of the salt's concentration.