Which of the following statements rigorously describe the underlying mechanisms that allow a mixture — Ionic Equilibrium Chemistry Question
Question
Which of the following statements rigorously describe the underlying mechanisms that allow a mixture of $CH_3COOH$ and $CH_3COONa$ to function as an effective buffer solution?
💡 Solution & Explanation
The mechanism of an acidic buffer heavily relies on Le Chatelier's principle and the common ion effect. The common ion ($CH_3COO^-$ from the salt) heavily suppresses the acid's ionization. If external $H^+$ is added, the abundant $CH_3COO^-$ ions capture it to form undissociated $CH_3COOH$. If external $OH^-$ is added, the undissociated $CH_3COOH$ donates a proton to neutralize it, forming $H_2O$ and $CH_3COO^-$. Water auto-ionization is irrelevant to the core buffer mechanism.