Exactly 100 mL of 0.12 M nitrous acid (HNO2) are titrated with a 0.12 M NaOH solution. Calculate the pH for the following.
(a) the initial solution
(b) the point at which 80 mL of the base has been added
(c) the equivalence point
(d) the point at which 105 mL of the base has been added