Throughout the series of SparkNotes on acidsbases, we have focused on calculating the pH of
solutions. Now, we'll take a look at a more practical side of acid-base
chemistry--how to
measure the pH of a solution.
The experiment that measures the pH of a solution is called a
titration. Titrations involve the
addition of a known amount of an acid or base to neutralize an unknown
amount of acid or base.
From the amount of acid needed to neutralize the base, or base to
neutralize the acid, one can calculate
the pH of the original solution. To detect the endpoint of a
titration, an indicator is used.
An indicator is an acid or base whose conjugate acid or conjugate
base has a different color
from that of the initial form. As the pH of the solution comes to equal the
pKa of the indicator,
a sharp color change is observed. We will examine how the shift of the
indicator to its conjugate form is related to the Henderson-Hasselbalch
equation.
An interesting property of titration is the titration curve--a plot of
solution pH versus
titrant volume. We can extract useful information from the titration curve
of a solution. In this SparkNote, we will study the different types of
titration curves and discuss
the chemistry behind them.
