You have 100 mL of a .10 M Acetate buffer pH 4.75 composed of .050 M Acetic Acid and .050 M Na Acetate. 100 ml of pure water is added and the pH is still 4.75. Use the henderson hasselbalch equation to explain what happened.
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H-H equation:
pH = pKa + log [Acetate-]/[Acetic acid]
When you dilute a buffer, you are not changing the ratio of conjugate base to conjugate acid. you are only changing their absolute concentrations. Since pH depends on the ratio of those concentrations, pH of a buffer does not change on dilution.
pH = pKa + log [Acetate-]/[Acetic acid]
When you dilute a buffer, you are not changing the ratio of conjugate base to conjugate acid. you are only changing their absolute concentrations. Since pH depends on the ratio of those concentrations, pH of a buffer does not change on dilution.