If equal volumes of the following are combined, would they form buffered solutions? Why or why not?
1) .1M NaC2H3O2 and .1M HF
2) .1M HF and .05M NaF
I'm am a bit confused about how I can figure out if these will form buffers or not, so I'd really appreciate it if someone could explain it to me. Thanks.
For a buffer you want a weak acid and a salt of the weak acid (#2 answer fills the bill) or a weak base and a salt of the weak base (example is NH3 and NH4Cl).
#1 is a weak acid (HF) and a salt of A weak acid (but not THE weak acid). Which Ka would you use? Ka for HF or Ka for HC2H3O2 in the Henderson-Hasselbalch equation. I tried some calculations with the HH equation and it appears that adding 5 mL of 0.1M NaOH or 5 mL of 0.1M HCl to a mixture of 100 mL 0.1M HF and 100 mL 0.1M Ac^- produces almost no buffer help. It appears, if I made no errors, that adding the HCl or NaOH would change the pH by as much as 1.3 pH units.