Which of the following pairs of solutions will form an acidic buffer when mixed in the stated volume — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

An acidic buffer requires a weak acid and its conjugate base. Mixing $100 \text{ mL } HCl$ with $200 \text{ mL } CH_3COONa$ converts half the $CH_3COONa$ into $CH_3COOH$, leaving $CH_3COOH$ and unreacted $CH_3COONa$, forming a buffer.