Determine the pH during the titration of 29.3 mL of 0.278 M hydroiodic acid by 0.274 M sodium hydroxide at the following points:
(1) Before the addition of any sodium hydroxide _______
(2) After the addition of 14.9 mL of sodium hydroxide _______
(3) At the equivalence point _________
(4) After adding 36.2 mL of sodium hydroxide _________