Titration

There is a variety of different color indicators available for determining the endpoint of a titration (Table 1). The best indictor to use for a titration depends upon the pH at the equivalence point. For example, if the pH at the equivalence point were 9.2, both thymol blue a phenolphthalein would be suitable indicators. The pH at the equivalence point is dependent upon the acid and base strength of the titrant and the solution being titrated. For example, when titrating a strong acid with a strong base, the pH at the equivalence point can be significantly different than the equivalence point of a titration between a weak acid and a strong base. Figure 1 illustrates an acid-base titration curve for the titration of 0.100 M HCl (a strong acid), with NaOH (a strong base).

Table 1