Weak Acids
Posted: Sun Nov 11, 2012 7:57 pm
In my textbook, it says some weak bases are the anions of weak acids, for example F- in HF. But I thought that the conjugate base of weak acids are strong bases?
Yes, in general the stronger an acid the weaker the conjugate base, and vice versa.
However, strength is relative. While there are acids stronger than hydroflouric, many are weaker.
At pKa=3.17, HF is a medium strength acid; and its conjugate F- is a very weak base at pKb = 10.83.
pKa + pKb = 14
http://chemed.chem.wisc.edu/chempaths/G ... s-958.html