How would you prepare a buffer (100ml) of pH 6.8 and concentration 0.1M given solid imidazole (mol wt.=68) and concentrated HCl

Answer 1

What's the pKa?
You have two equations.
#1 is pH = pKa + log (base)/(acid)
6.8 = pKa + log b/a

#2 is a + b = 0.1
Solve these two equations for (acid) and (base).

Calculate grams base needed, add to 100 mL of water, place in a pH meter, add HCl to the desired pH.