1

Beginning – pH rises gradually as base added, pH remains relatively constant event though small amounts of base are being added – first amount of titrants are immediately consumed, leaving excess of strong acid 2

After this flat region, there is a very rapid increase in pH for a very small additional volume of titrant. The MIDPOINT of the sharp increase in pH occurs at a pH of 7.00 – the equivalence point of the reaction and corresponds to the endpoint of titration (with an appropriate indicator) – the neutralization point 3

Finally, the curve bends to reflect a more gradual increase in pH as excess base is added 4

In a titration, 20.0 mL of mol/L HCl(aq) is titrated with standardized mol/L NaOH(aq). What is the amount of unreacted HCl(aq) and the pH of the solution after the following volumes of NaOH(aq) have been added? (a) 0 mL(b) 10.0 mL (c) 20.0 mL(d) 21.0 mL 5