Aniline hydrochloride, (C6H5NH3)Cl, is a weak acid. (Its conjugate base is the weak base aniline, C6H5NH2.) The acid is titrated with a strong base such as NaOH.
Assume 50.0 mL of 0.100 M aniline hydrochloride is titrated with 0.185 M NaOH. (Ka for aniline hydrochloride is 2.4×10-5.)
(a) What is the pH of the (C6H5NH3) solution before the titration begins?
(b) What is the pH at the equivalence point?
(c) What is the pH at the halfway point of the titration?
(d) Which indicator could be used to detect the equivalence point?
(e) Calculate the pH of the solution after adding 10.0, 20.0, and 30.0 mL of the base.
(f) Combine the information in parts (a), (b), (c), and (e), and plot an approximate titration curve.
