A solution that contains 0.710% C₅H₅N by mass and 0.845% C₅H₅NHCl by mass (where pKa=5.23 for C₅H₅NHCl acid) express your answer using two decimal places.
a) pH = 4.98
b) pH = 5.67
c) pH = 6.32
d) pH = 7.01