Sleeping pills often contain barbital, which is weakly acidic (pKa = 8.00). For analysis of the barbital content of a sleeping pill, a titration is carried out with strong base. It takes 12.00 mL of 0.200 M base to reach the stoichiometric point. If the initial acid concentration is 0.0120 M and the solution volume is 200. mL, what is the pH of the solution after adding the following volumes of base solution:
a) 0.0 mL added base
b) 4.7 mL added base
c) 6.00 mL added base
d) 12.00 mL added base
e) 13.8 mL added base