Question

If you had a "sour stomach," you might try an over-the-counter antacid tablet to relieve the problem. Can you think of evidence that the action of such an antacid is a chemical reaction?

Short answer

The action of an antacid tablet is a chemical reaction because it involves the formation of new products, such as calcium chloride, water, and carbon dioxide, when the tablet's base reacts with stomach acids like hydrochloric acid. This reaction is known as an acid-base or neutralization reaction. Evidence supporting this claim includes the release of gas (carbon dioxide) and a change in the pH level of the stomach contents, both of which indicate a chemical reaction has taken place.

Step-by-step solution

Basic understanding of an antacid tablet

Antacid tablets typically contain a base such as calcium carbonate, magnesium hydroxide, or sodium bicarbonate. These substances neutralize the excess stomach acid by reacting with the hydrochloric acid (HCl) in the stomach, which regulates the overall pH levels inside the stomach and eases the symptoms of a sour stomach.

Identify the chemical reaction taking place

The reaction taking place when an antacid tablet is consumed is an acid-base reaction, also known as a neutralization reaction. The reaction occurs between the base in the antacid and the hydrochloric acid present in the stomach. For example, when calcium carbonate (CaCO3), a common antacid ingredient, reacts with hydrochloric acid (HCl), it forms calcium chloride (CaCl2), water (H2O), and carbon dioxide (CO2). This can be represented as follows: CaCO3 + 2HCl → CaCl2 + H2O + CO2

Evidence of a chemical reaction

There are a few pieces of evidence supporting the idea that an antacid tablet undergoes a chemical reaction upon consumption: 1. Formation of new products: In the case of the chemical equation mentioned earlier, the products of the reaction are different from the reactants. Calcium chloride, water, and carbon dioxide are formed as a result of the reaction, which is an indication of a chemical reaction. 2. Release of gas: During the reaction, carbon dioxide is produced, which may be observed as gas bubbles when an antacid tablet is dissolved in water or when it comes in contact with stomach acid. The release of a gas indicates a chemical change. 3. Change in pH: The overall purpose of an antacid tablet is to alleviate a sour stomach by neutralizing the excess stomach acid. This is achieved through a change in the pH level of the stomach contents after the tablet has been digested. A change in pH is another sign of a chemical reaction. Overall, these observations indicate that the action of an antacid tablet is, indeed, a chemical reaction.