[Olympiad] Calculate the pH of a buffer solution composed of 0.2 M acetic acid and 0.5 M sodium acetate. (pKa for acetic acid = 4.76)
- 4.10
- 5.16
- 5.46
- 7.00
📝 Detailed explanation
Using Henderson-Hasselbalch equation: pH = pKa + log([Salt]/[Acid])pH = 4.76 + log(0.5/0.2) = 4.76 + log(2.5) = 4.76 + 0.398 = 5.158 ≈ 5.16.