What is the pH for a buffer that consists of 0.45 M CHv3COOH and 0.35 M CHv3COONa Kva = 1.8 x 10^-5?

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What is the pH for a buffer that consists of 0.45 M CHv3COOH and 0.35 M CHv3COONa Kva = 1.8 x 10^-5?

2007-08-17 18:59:36 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry

2 answers

We can use Henderson-Hasselbalch equation
pH = pKa + log [ CH3COO- ] / [CH3COOH ]
pKa = - log Ka = - log 1.8 x 10^-5 = 4.74
pH = 4.74 + log 0.35 / 0.45 = 4.63

2007-08-18 01:52:16 · answer #1 · answered by Dr.A 7 · 0⤊ 0⤋

[H+] = Ka x 0.45/0.35.

Then simply take the negative log of [H+] for your answer.

2007-08-17 19:33:57 · answer #2 · answered by Gervald F 7 · 0⤊ 0⤋