posted by dude of pluto .
Indicate the approximate of pH of a buffer made from equal concentrations of each of these pairs
The Henderson-Hasselbalch equation for buffers is
pH = pKa + log (base/acid)
If you want (base) = (acid), then log base/acid is log 1 and that is zero; therefore, pH is pKa. Just look up the pKa for the acid of each pair and that will be the pH.