Calculate the pH of a solution that is 0.6 M
in sodium acetate and 0.2 M in acetic acid.
Ka = 1.8 x 10-5 for acetic acid.
2007-11-21 15:34:09 · 2 answers · asked by Jack L 1 in Science & Mathematics ➔ Chemistry
Why don't you try the Henderson Hasselbach equation for that. It's plug and chug.
2007-11-21 15:43:48 · answer #1 · answered by Fly On The Wall 7 · 0⤊ 0⤋
You need an equilibrium relation
HOAc = OAc- + H+
You can choose to start with either the acid first and then the sodium salt or vice versa. If you start with the salt, it is totally ionized [OAc-] = 0.6 M, and the amount that reacts with H+ to form HOAc is << 0.6 M. So the conc of HOAC= 0.2 M.
Then [H+][OAc-]/[HOAc]= 1.8x10-5
Substituting, 3[H+] = 1.8x10-5, or [H+]=6x10-6.
So pH =6-log 6= 5.22 appx
2007-11-21 23:46:57 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋