Chemistry 163
Kw = [H+][OH-] = 1x10-14
Name_________________________
pH = -log [H+]
pOH = -log[OH-]
Titration Exercise: For each calculation, start with 50.0mL of a 0.950M solution of methylamine
CH3NH2 (Kb = 4.4x10-4) in a flask. In the buret above you have HCl that is 1.000M.
Calculate the following at each step of your titration: pH, [CH3NH2], [CH3NH3+]
1. At the start of your titration (before any HCl has been added).
2. After addition of 20 mL total of HCl
3. After addition of 30 mL of HCl (30 mL HCl total added)
4. After addition of 50 mL of HCl (50mL total HCl added)
5. What volume of HCl must be added to reach the titration equivalence point?
a. What is the pH at the equivalence point?
6. What volume of HCl must be added to reach the titration midpoint?
a. What is the pH at the midpoint?
7. Draw a titration curve showing each point from the titration above (1-6). Label all
the parts of your graph (equivalence point, mid point, axes, buffer region, etc…).