Dear all,
I want to prepare a 0.1 M Sodium Acetate Buffer Solution with pH=5.0-6.0. I don't know what the appropriate amount of acetic acid and sodium acetate should be used for that? So, How can I adjust the pH?
Thank you very much in advance.
Dear Muhammad,
To prepare your 0.1 M sodium acetate buffer, you should: 1) dissolved ca. 17g of sodium acetate, 2) in 12 mL of glacial acetic acid + 1994 mL of pure water. To fix the pH at 5, you should use 10 N NaOH solution.
Another solution is to mix 357 mL of 0.1 M acetic acid with 643 mL of 0.1 M sodium acetate and your pH will be fixed at 5. If you want a pH value of 6, do this following mixture: 52.2 mL of 0.1 M acetic acid plus 947.8 mL 0f 0.1 M sodium acetate. The solution of 0.1 M sodium acetate is done from the dissolution of 13.6 g of sodium acetate trihydrate in 1 L of pure water.
I hope that two possibilities will help you,
Best regards,
Marjorie
The pKa of acetic acid is 4.75, from what we can only expect fair pH buffering effect between approx. 3.75 to 5.75. The pH of acetic acid / sodium acetate buffer solutions can be simply calculated based on the Henderson-Hasselbalch equation, after the molar concentrations of acetic acid (Ca) and sodium acetate salt (Cs) at the buffer solution: pH = pKa + log10(Cs/Ca); what can be generally expected to hold for Ca > 100Ka. A possible derivation for this equation, along with a justification for the stated minimum concentration limit for its validity, can be found elsewhere at this forum: https://www.researchgate.net/post/pH_calculation_of_a_mixture_of_formic_acid_NaOH_and_water
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