Buffer regions / titration curve of ammonium acetate

[khimik]

Hi all,

Can anyone direct me to a titration curve for acetic acid titrated with ammonium hydroxide, or vice versa? I don't have direct access to an autotitrator any more so I can't generate one myself. Don't have time to do it manually, either.

I need to know what the effective buffering ranges are for ammonium acetate. Here's what I do know: 1) it's a salt of a weak acid and a weak base, so most textbooks won't touch it with a 10-ft pole 2) the pH of a neat solution is about 7.0 3) the pH jump a the equivalence point is very small, suggesting the buffering regions are broader and more tilted than the typical s-curve. But I need firmer information. Can anyone help?

Thanks!
khimik

[HW Mueller]

One can calculate what you need via buffer index formulars (sometimes called buffer capacity). Any book on chemical equilibrium, or on buffers, will elucidate on this. My old book from student days, Butler, Ionic Equilibrium, Addison-Wesley, 1964 has a diagram of the buffer index of NH4AcO on page 242. It´s essentially a composite of the buffer indicese of NH3 and HOAc.