The easiest way of measuring how much of an unknown acid or base
is present in solution is to neutralize it with just enough base
or acid to bring the pH to 7.00, as measured by an acid-base indicator
or other means.
At neutrality, the number of equivalents of acid and base must
be the same. This process of neutralization as a means of measuring
the amount of unknown acid or base present is known as titration.
The sample to be measured and a small amount of acid-base indicator
are placed in a beaker, and the titrating base or acid is added
from a graduated burette, as shown on the previous page, until a
change of color of the acid-base indicator in the sample solution
shows that neutralization, or the end point, has been reached.
Example. A solution of acetic acid of unknown concentration
is titrated against 0.01-molar KOH, and it is found that 83 mil
of base are required for complete neutralization of the acid.
How many equivalents, and how many grams, of acetic acid were present?