Question

You've been experiencing acid indigestion lately, and you'd like a quick fix for the problem. You do a little research on the Internet and discover that your problem is caused by excess stomach acid. In the pharmacy aisles, however, you're having a little trouble deciding what to purchase to address the problem. At the pharmacy counter, the clerk recommends that you purchase PEPCID AC or Alka-Seltzer tablets. You hypothesize that a tablet of PEPCID AC can neutralize more stomach acid than a tablet of Alka-Seltzer. If you placed a tablet of each antacid in a beaker of acid at an initial pH of 2, which of the following experimental results would support your hypothesis? A. After 1 hour, the pH of the solution in the PEPCID AC beaker was 7.9 and the pH of the solution in the Alka-Seltzer beaker was 9.6. B. It took 3 minutes for the PEPCID AC tablet to fully dissolve, and it took 5 minutes for the Alka-Seltzer tablet to fully dissolve. C. After 1 hour, the pH of the solution in the PEPCID AC beaker was 9.2 and the pH of the solution in the Alka-Seltzer beaker was 8.3. D. After 1 hour, the pH of the solution in the PEPCID AC beaker was equal to that of the pH of the solution in the Alka-Seltzer beaker.

Answer 1

Answer:

C: After 1 hour, the pH of the solution in the PEPCID AC beaker was 9.2 and the pH of the solution in the Alka-Seltzer beaker was 8.3

Explanation:

The degree of acidity or alkalinity/basicity of a substance is its pH. The value of pH ranges from 1 to 14 with the former being extreme acidity and the latter being extreme alkalinity while pH 7 is considered neutral.

Hence, any pH below 7 is considered acidic and above 7 is considered alkaline.

Reactions involving equal volumes of an acid and a base can end in acidic, alkaline or neutral pH depending on the strength of the acid/base involved;

• Equal volumes of strong acid with strong base will result in neutral pH
• Equal volumes of weak acid with strong base will result in alkaline pH
• Equal volume of strong acid with weak base will result in acidic pH

If substance A and B reacts with equal volume of the same acid under the same condition and the end result of A is a solution with pH of 9.2 and that of B is a pH of 8.3, it simply means substance A is a stronger base than substance B.

Hence, the only outcome that supports the hypothesis that a tablet of PEPCID AC can neutralize more stomach acid than a tablet of Alka-Seltzer is that the pH of the solution in the PEPCID AC beaker was 9.2 and the pH of the solution in the Alka-Seltzer beaker was 8.3 after being subjected to the same condition.

If an indigestion is due to excess stomach acid, the only way to reduce the acidity is to consume a substance that will decrease the degree of acidity in the stomach. This means that the patient will need to consume something that is alkaline in order to increase the pH.