HEPES,2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonicacid, is a diprotic acid often used to
create buffers compatible with biological samples. A 10.0 mLsample of HEPES was titrated with
0.100 M NaOH.
a. To 2 places past the decimal point, determine the values ofpKa1 and pKa2 for HEPES
b. Calculate the initial molarity of the HEPES solution to 4 sigfigs.
c. A 20.0 mL portion of 0.20 M HEPES is titrated with 0.100 MNaOH. Calculate the pH at the first
and second equivalence points of the titration.
