Which of the following will occur if a solution of a weak acid is diluted to at constant temperature — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

Upon dilution, the concentration ($C$) decreases. By Ostwald's dilution law, the degree of ionization $\alpha \approx \sqrt{K_a/C}$, so percentage ionization increases as concentration drops (Option C is true). The hydrogen ion concentration $[\text{H}^+] \approx \sqrt{K_a C}$, so diluting the solution decreases $[\text{H}^+]$ (Option A is true). A decrease in $[\text{H}^+]$ leads to a corresponding increase in pH (Option B is true). The acid dissociation constant $K_a$ depends only on temperature and remains unchanged (Option D is false). Therefore, correct answer is A,B,C.