Lab 17: Measuring the pH of Acids and Bases
To determine experimentally the pH of several acid, base, and salt solutions.
CAUTION: Students must wear departmentally approved eye protection while performing this experiment. Wash your
hands before touching your eyes and after completing the experiment. If acid or base contacts your skin, wash the affected
area with copious quantities of water. Be especially cautious with all the solutions, they are extremely caustic and
A pH meter and its electrodes form a sensitive electrochemical device that will allow an accurate,
reproducible, and reliable measurement of the pH of a solution. A pH meter is essentially
a voltmeter that measures the voltage of an electric current flowing through a solution between two electrodes.
There is a direct relationship between the voltage and the pH of a solution. As a result, the meter on
the instrument is calibrated directly in pH units.
Although the operating rules for a pH meter will depend on the model and the manufacturer, there are several
steps that must be followed with any pH meter: