A buffer is prepared using acetic acid, CH3COOH, (a weak acid, pKa = 4.75) and sodium acetate, CH3COONa (which provides acetate ions, the conjugate base), according to the following proportions:
The volume of CH3COOH(aq): 141.0 mL
The concentration of CH3COOH(aq): 1.062 M
Volume of CH3COONa(aq): 110.0 mL
Concentration of CH3COONa(aq): 1.162 M
Use the Henderson-Hasselbalch equation to calculate the pH of the buffer solution.
pH Chemistry?
2020-04-08 3:39 pm
回答 (1)
2020-04-08 3:55 pm
✔ 最佳答案
In the final solution:Moles of CH₃COOH = (1.062 mol/L) × (141.0/1000 L) = 0.1497
Moles of CH₃COO⁻ = (1.162 mol/L) × (110.0/1000 L) = 0.1278
[CH₃COO⁻]/[CH₃COOH] = (Moles of CH₃COO⁻)/(Moles of CH₃COOH) = 0.1278/0.1497
CH₃COOH(aq) + H₂O(ℓ) ⇌ CH₃COO⁻(aq) + H₃O⁺(aq) … pKa = 4.75
Henderson-Hasselbalch equation:
pH = pKa + log([CH₃COO⁻]/[CH₃COOH])
pH = 4.75 + log(0.1278/0.1497)
pH = 4.68
收錄日期: 2021-04-18 18:27:41
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