EFFECTIVENESS OF COMMERCIAL ANTACIDS INTRODUCTION pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7. 0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. An antacid is a substance which neutralizes stomach acidity. Antacids perform a neutralization reaction, increasing the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed.

Antacids are taken by mouth and work by neutralizing excess stomach acid. They contain ingredients such as aluminum hydroxide, calcium carbonate, magnesium hydroxide, and sodium bicarbonate, alone or in various combinations. Antacid products may also contain other ingredients such as simethicone, which relieves gas. Antacids differ in how quickly they work and how long they provide relief. Those that dissolve rapidly in the stomach, such as magnesium hydroxide and sodium bicarbonate, bring the fastest relief. Antacids that contain calcium carbonate or aluminum dissolve more slowly and can take up to 30 minutes to begin working.

The longer an antacid stays in the stomach, the longer it works. Those that contain calcium carbonate or aluminum work longer than those that contain sodium bicarbonate or magnesium. Also, taking any kind of antacid after a meal, instead of on an empty stomach, provides longer-lasting relief because the medicine stays in the stomach. PROBLEM What particular drug among Alka-seltzer, Rolaids and Tums is more effective when it comes to neutralizing acidity of the stomach? HYPOTHESIS/PREDICTION If a certain drug needs higher amount of drops in order for it to change its color, then that particular drug is a good buffer.

MATERIALS Alka-Seltzer Rolaids Tums 0. 1 M hydrochloric acid (HCl) PROCEDURE 1. Use mortar and pestle to pulverize the amount of antacid that is listed as one dose. Dissolve the crushed antacid in 100 ml of distilled water. Some of the products may require extensive stirring to get most or all of the powder to dissolve. 2. Using a pipet or 10-ml graduated cylinder add 5 ml of the antacid solution into a test tube. Add 4 drops of the indicator bromcresol purple to the tube. Cover the tube with Parafilm and invert the tube to mix the contents. 3. Add 0. 1 M HCl dropwise to the tube; mix after each drop.

Continue this process until the solution turns yellow, indicating an acidic solution. 4. Record in table the number of drops of acid needed to generate the change of color. This number of drops is an index to the amount of acid that the solution neutralizes before the pH drops below the yellow endpoint of bromcresol purple. SAFETY Although majority of the materials do not cause harm, still handle all solutions carefully. RESULTS Solution| Drops of acid| Alka-seltzer| 185| Rolaids| 7| Tums| 11| ANALYSIS Based on the results, Alka-seltzer has the most number of drops which is 185 before the solution turns to yellow.

Rolaids and Tums have 7 and 11 respectively. CONCLUSION Alka-Seltzer has resists 185 drops before it turns to yellow (acidity). Therefore, Alka-seltzer is more effective when it comes to neutralizing acidity of the stomach compared to the other solutions in this experiment. References: Vodopich, Darrel, and Randy Moore. Biology Laboratory Manual. 9thth ed. N. p. : The McGraw-Hill Companies, Inc, 2011. 60. Print. http://en. wikipedia. org/wiki/PH http://en. wikipedia. org/wiki/Antacid http://www. faqs. org/health/topics/50/Antacids. html