What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.89 at 25°C? K_a for HC₂H₃O₂ is 1.8 $\times$ 10^-5.

Question

Quizplus · Accepted Answer

The pH of a buffer solution is given by the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]). The pKa of acetic acid is -log(1.8 x 10^-5) = 4.74. To find the ratio [A-]/[HA], rearrange the equation: log([A-]/[HA]) = pH - pKa = 4.89 - 4.74 = 0.15. Therefore, [A-]/[HA] = 10^0.15 ≈ 1.41. The inverse of this ratio is approximately 0.72, which corresponds to the ratio of acetic acid to sodium acetate.

What Molar Ratio of Acetic Acid to Sodium Acetate Is ×\times×

What Molar Ratio of Acetic Acid to Sodium Acetate Is $\times$