Which Antacid Can Neutralize The Most Stomach Acid?

Researched by Nicole B. 


    The purpose of this experiment was to determine which antacid could neutralize the most stomach acid.
    I became interested in this idea when I saw some experiments on medicines and wanted to find out some scientific facts about medicines.
    The information gained from this experiment will help people know which antacid they should look for in the stores.  It will also let them know which antacid will give them the most comfort.  This could also save consumers money and provide better heath.


    My hypothesis was that Tagamet would neutralize the most stomach acid.
I base my hypothesis on the information that Tagamet has the active ingredient of cimetine and it is very alkaline.


    The constants in this study were:
- The length of time the mixture sat in the water.
- The amount of water
- Type of acid
- Consistency of procedures
    The manipulated variable was:

-Different types of antacids added to the water
-Different amounts of stomach acid.
    The responding variable was:
- The amount of stomach acid each antacid could neutralize measured in ml.
    To measure the responding variable I used a machine called a pH meter to show the neutralization and a burret filled with HCL to exactly measure the volume of acid used.

500ml Stomach acid (Hydrochloric Acid)
1,200ml. Cold Water pH of 7.55
2 Pair Latex gloves
4 Different antacids
1 Magnestir
Pair protective goggles
1 Science apron
4- 200 ml Vials
1 Buret
1 Rubber Policemen
Hot water bath
1 Bowl and Pistle
1 pH Meter


1. Get the 4, 200ml glass vials
2.  Get 1,200 ml of cold water
3. 500ml of stomach acid
4. Fill each vial with 100 ml of water
5. Crush one dosage of each antacid.
6. Put one dosage of each antacid in a different vial.
7. Mix until the antacid is fully dissolved in the water.
8. Soak in hot water bath.
9. Test initial pH.
10.  Fill an burette with approximately 50 ml of ìstomach acidî (Hydrochloric Acid.)
11. Drop one drop of acid into the antacid mixture and stir.
12. Repeat step 11 counting the number of drops it takes to make the pH reach 7.0.
13. Record the number of drops in data table.
14. Repeat  entire experiment 2 more times
15.When finished average up your data to come up with an overall conclusion.



The original purpose of this experiment was to determine which antacid would neutralize the most stomach acid.  The different antacids I used were Tums, Tagamet, MAALOX, and Pepcid AC.  In an antacid it is not the name brand that tells how well it works it is something called an active ingredient.  Not all antacids have a different active ingredient.  Some have one of the same active ingredients and some have all of the same active ingredients.  Almost all the antacids that have the same active ingredient work the same amount as the other.  Now you know that the name brand doesnít matter it is the active ingredient.
The results of the experiment were that the antacid Tums neutralized the most stomach acid.


My hypothesis was that the antacid Tagamet would neutralize the most stomach acid.

The results indicate that this hypothesis should be rejected.  Tums are my over all antacid they have the active ingredient of Calcium carbonate and magnesium hydroxide.  I think Tums neutralized the most stomach acid because it has calcium carbonate in it.  Calcium carbonate is proven to be highly alkaline.

Because of the results of this experiment, I wonder if the amount of buffer in the antacid had an effect on how much stomach acid the antacid neutralized.  I also wonder if some products sold as antacids work in a different way than those that are quite basic.

If I were to conduct this experiment again I would make more observations on the experiment.   I would focus on active ingredients other than antacid brands such as cimetidine( Tagamet).  I also would use phenolphthalein as an indicator of when an acid is neutralized.




Antacids help people who have or get heartburn. The following information will help people understand how stomach acid works and what antacid will help them most.


Stomach acid is very dangerous.  If a person were to have an ìulcerî and the stomach acid were to escape it would ìeatî their other organs.  Stomach acid is highly acidic and has a pH of 1.6.  Stomach acid is hydrochloric acid produced by the stomach.  If there is too much stomach acid it can cause heartburn.  Heartburn is when stomach acid is produced in abnormal amounts or location.  One of the symptoms of heartburn is a burning feeling in the chest or abdomen.


Acids are a group of chemicals, usually in liquid form.  They can be recognized by their sour taste and their ability to react with other substances.  Acids are confirmed as an acid by their pH.  The pH of acids range from 0-6.9.  The two main acids are: mineral acid and organic acid.  The three acids that are most common are sulfuric acid (H2SO4), nitric acid (HNO3), and hydrochloric acid (HCL).


An antacid is any substance that can neutralize an acid.  All antacids are bases.  A base is any substance that can neutralize an acid.  The pH of a base is 7.1-14.  All antacids have chemical in them called a buffer. When an antacid is mixed with an acid the buffer tries to even out the acidity and that is how stomach acid gets neutralized.


Almost all foods and drinks and even medicines have ingredients that are different acids.  Here are some examples: Aspirin (acetylsalicylic acid), Orange Juice (ascorbic acid/Vitamin C), Sour Milk (lactic acid), Soda Water (carbonic acid), Vinegar (acetic acid), Apples (malic acid), and Spinach (oxalic acid).


 Antacids are commonly used to help neutralize stomach acid.  Antacids are bases with a pH above 7.0 that chemically react with acids to neutralize them.


ìAntacidî, Microsoft Encarta, 1998, Disk One

Be? Langer, Patrice C., ìPhenolphthaleinî, World Book Encyclopedia, 1991, 15, 356

Houghton Mifflin Company, Student Dictionary, New York, Houghton Mifflin Company, 1994, 41

Knapp, Brian ñ BSc, Ph.D., Hydrogen and the Noble Gasses, Europe, Atlantic Europe Publishing Co. Ltd., 1996, 17 ñ 20

Root, Walter S. ìStomachî, Microsoft Encarta, 1998, Disk One

Rose, Emily Jane ìAcidî, World Book Encyclopedia, 1991, 1, 26 ñ 27

Rose, Emily Jane, Base , USA, 1987, 123

Causes of Heartburn,http://www.mindspring.com/~videosur/lscauhb.html, 12/16/98

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