If pH = -log[H+] then does that mean that the pH for this CH3COOH 1.0M solution is 0? Thanks.
2007-09-22 07:50:52 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Assuming 100% dissociation. Sorry!
2007-09-22 08:46:12 · update #1
No, because CH3COOH is only a few percent ionized. The amount of ionization of acetic acid (call it HOAc) is governed by its acidity constant, ionization constant, Ka, which is:
Ka = [H+][OAc-] / [HOAc] = 1.85 x 10^-5
Let [H+] = [OAc-] = x and [HOAc] = 1.0M
x^2/1.0 = 1.85 x 10^-5
x^2 = 1.85 x 10^-5 = 18.5 x 10^4
x = 4.3 x 10^-2
Log [H+] = -1.3
pH = 1.3
2007-09-22 08:03:34 · answer #1 · answered by steve_geo1 7 · 0⤊ 0⤋
No, because it's only very slightly ionised.
pH = -log (root [1.0 x Ka for ethanoic acid])
2007-09-22 14:57:39 · answer #2 · answered by Gervald F 7 · 0⤊ 0⤋