[CH3COOH]=0.1 mol dm-3 and that for [CH3COONa]=0.1 mol.dm-3 the pH of buffer is [pKa=4.74]:
Correct answer: B. 4.74
- A. 5.74
- B. 4.74
- C. 3.74
- D. 0
Explanation
The pH of a buffer solution is calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]) where: pH is the pH of the buffer solution pKa is the pKa of the weak acid [A-] is the concentration of the conjugate base [HA] is the concentration of the weak acid.In this case, we are given that the pKa of acetic acid is 4.74, and that the concentrations of acetic acid and sodium acetate are both 0.1 mol dm-3.Substituting these values into the Henderson-Hasselbalch equation, we get: pH = 4.74 + log([CH3COO-]/[CH3COOH]).Therefore, the pH of the buffer solution is 4.74.
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