Which chemical combination forms an effective acidic buffer solution capable of resisting changes in pH upon minor additions of acid or base?
Answer and explanation
Correct answer: A. ethanoic acid and sodium ethanoate
- Step 1: An acidic buffer requires a weak acid and its conjugate base (salt with a strong base). Step 2. Ethanoic acid (CH₃COOH) is a weak acid and sodium ethanoate (CH₃COONa) provides the conjugate base (CH₃COO⁻). Step 3. Strong acids like HCl or H₂SO₄ cannot form buffer systems. Answer: ethanoic acid and sodium ethanoate. Why not the others: HCl and H₂SO₄ are strong acids; NaOH is a strong base with a neutral salt.
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