Answer to Question #56206 in General Chemistry for jocelyn

Question

explain the difference between equivalence point and the end point

Answer 1

An equivalence point of titration relates to the theoretical completion of the titration. For instance, upon acid-base titration the equivalence point is at pH = 7, when all acid reacts with equivalent amount of base.
Usually, it is quite difficult to find an exact equivalence point in each experiment. Therefore, during the titration the end point is determined. This is the closet point behind the equivalence point when the change of color of indicator occurs. For example, phenolphtalein (the change of color at pH = 8.2 - 10) and methyl orange (the change of color at pH = 3.2 - 4.4) are commonly used for acid-base titration.
The value which equals the difference between equivalence point and the end point is known as an indicator error.