Concept #1: Whenever starting these titrations it is best to determine the equivalence volume of the titrant.
Concept #2: Before the equivalence point has been reached we have the formation of a buffer.
Concept #3: At the equivalence point we have no remaining weak acid or strong base, but instead an excess of conjugate base.
Concept #4: Beyond the equivalence point we will have an excess of strong base and conjugate base remaining.
Example #1: A 250.0 mL solution of 0.100 M HClO is titrated with 0.200 M NaOH. What is the expected pH of the resulting solution once 50.0 mL of the NaOH solution has been added to the HClO solution?
Example #2: A buffer contains 155.3 mL of 0.480 M nitrous acid, HNO2, with 100.0 mL of 0.550 M lithium nitrite, LiNO2. Find the pH after the addition of 125.0 mL of 0.400 M LiOH. The Ka of HNO2 is 4.6 x 10-4.