Buret preparation and calibration and cost analysis of antacids using the
method of titration
Chemistry 100A at University of California, San Diego
9500 Gilman Drive, La Jolla, California 92093
10 July 2006
The method of titration using a buret was used to perform cost analysis of two different brands of
antacids. In the first part of the experiment, familiarity with the buret was achieved through its
preparation and calibration, which also helped to minimize indeterminate errors. From the calibration,
the volume per drop value was determined to be 0.0525 ± 0.0013 mL/drop while the drops per volume
was 19.06 ± 0.48 drops/mL In the second part, two brands of antacids, Tums and Longs Acid Relief
Antacid Tablets, were titrated twice, first with 1 M HCl and then the excess acid from that titration was
titrated with 0.100 M NaOH. The calculated cost per mole of acid neutralized for Tums is $1.93 while
the cost per mole of acid neutralized for the Longs Acid Relief Antacid Tablets is $3.05, which
significantly higher than Tums.
It is estimated that “Americans currently spend close to $1 billion yearly on over-the-counter
What are the causes of this huge amount of spending? The answer to this question first
requires brief knowledge about the digestive system and its pH dependence.
The parietal cells on the inner lining of the stomach (called the mucosa) secrete hydrochloric
acid (HCl) and help maintain a healthy acidity level of pH 1-2, which is desirable for the digestion of
food. “The stomach is [also] lined by a…mucus layer that acts as a barrier and protects the mucosa
against the acidic environment, proteolytic enzymes, and mechanical damage.”
However, once the pH
deviates from this normal level due to overproduction of acid, the defense system is not as effective and
problems such as Helicobacter pylori infection can lead to gastric and duodenal ulcers and ultimately,
Hence, substances that can neutralize excess acid in the stomach called antacids are
important for this purpose and for solving other health issues such as indigestion and acid stomach.
There are several different brands of over-the-counter antacids nowadays, each sold in different
quantity and at different prices. Since Americans are spending a considerable amount annually
purchasing these products, how can one determine if what we are paying is the right for its
effectiveness? Therefore, the purpose of this experiment is to use the method of titration, after careful
preparation and calibration of the buret, to perform cost analysis of two of the most popular brands,
Tums and Longs Acid Relief Antacid Tablets. Afterwards, a comparison their costs per moles of acid
neutralized can help determine which of the two gives the best result for our money’s worth.