1. What is the pH of a buffer that contains 0.15 M CH3COOH and 0.10 M NaCH3COO (Ka = 1.8 × 10–
To find the pH of the buffer solution, we need to use the Henderson-Hasselbalch equation:
pH = pKa + log ([A−]/[HA])
Given that Ka = 1.8 × 10^(-5) for CH3COOH, we can calculate pKa as follows:
pKa = -log(Ka) = -log(1.8 × 10^(-5)) ≈ 4.74
Plugging in the values into the Henderson-Hasselbalch equation:
pH = 4.74 + log (0.10/0.15)
pH = 4.74 + log (0.6667)
pH = 4.74 - 0.1761
pH ≈ 4.56
Therefore, the pH of the buffer solution containing 0.15 M CH3COOH and 0.10 M NaCH3COO is approximately 4.56.