ANTACID NEUTRALIZATION
Claudia Zimmerman
Cary Academy
ABSTRACT
The purpose of this experiment was to determine which antacid can neutralize an acid the most. The
amount of hydrogen ions in any solution affects the pH. Three antacids were dropped into a beaker
and the pH was tested to see which one neutralizes acid the most. Pepto-Bismol and Tums
neutralized the acid the most and none neutralized the acidity the least. Pepto-Bismol and Tums did
the best because Tums is made of Calcium Carbonate and Pepto-Bismol is made of bismuth
subsalicylate and these are both common antacids.
INTRODUCTION
pH is the amount of the hydrogen ions in a solution. The amount of hydrogen ions in can affect the
solution color. The amount of hydrogen ions in soil can affect the color of the plants and flowers. For
example, pink hydrangeas are grown in a basic soil and blue hydrangeas are grown in acidic soil.
There is a pH indicator. The pH indicator is universal. Pink is extremely acidic, purple is extremely
basic, and yellow is neutral. When acids and bases mix they usually neutralize. Most of the time
acids and bases are thought of as opposites.
Figure 1. The pH strip turns pink when extremely acidic and turns purple when extremely basic.
The more hydrogen ions the stronger the acid and the fewer the hydrogen ions the less acidic the
solution is. In chemistry the word “acid” has a specific and precise definition. The definition is a
chemical compound that dissociates in solution, releasing hydrogen ions and lowering the solution pH
(a proton donor). A pH of one and two are strong acids. Things in nature also have pH, such as a
bee sting. The sting of a bee is acidic. Ammonia is a household cleaner that is a base. When
hydrangeas are grown in a basic soil they turn pink. pH’s above 7 are considered acids. pH’s below
7are considered bases. Lead battery acid is an extremely acidic solution. Soda lye is an extremely
basic solution.
An antacid is any substance that neutralizes acidity. Antacids are used to neutralize acids. Antacids
that come over the counter usually neutralize the acidity. In many over the counter antacids the main
ingredient is baking soda. Other common ingredients in antacids are aluminum hydroxide, bismuth
subsalicylate, sodium bicarbonate, magnesium hydroxide, and calcium carbonate.
Experiments like this have been done in the past by Coleman Mitchell. He is from Cary Academy.
He tested which type of soda an Alka-Seltzer tablet would dissolve in fastest. He used 7up, Sprite,
Ginger Ale, and water. 250 mL were put into a beaker and the pH was tested and recorded. He
found out that Ginger Ale was the most acidic with a pH of 3. Another experiment that he did was
measuring how long it took for an Alka-Seltzer tablet to dissolve. He found out that an Alka-Seltzer
dissolves fastest in water. The Alka-Seltzer dissolved in water with a time of 66 sec. With his third
experiment that he did was measuring Alka-Seltzer tablets in different amounts of water. He found
that an Alka-Seltzer tablet will dissolve fastest in 150 mL of water. It took 60 sec for the Alka-Seltzer
tablet to dissolve in 150 mL of water. For his fourth experiment, he tested different amounts of AlkaSeltzer in 7up. He found that one tablet dissolved in the least amount of time. One tablet dissolved
in 7up in 90 sec. Coleman did this experiment again but this time using Ginger Ale. Again one tablet
dissolved in Ginger Ale the fastest. One tablet dissolved in 65 sec. Coleman’s final experiment was
like his fifth and sixth. This time he used sprite. Again, one tablet dissolved the fastest. One tablet in
sprite dissolves in 85 sec. These were experiments done by Coleman Mitchell.
The idea or concept of pH was first introduced by a Danish chemist. He was named Søren Peder
Lauritz Sørensen. In 1909, he introduced the idea of pH at the Carlsberg Laboratory. From 1901 to
1938 he was head of the prestigious Carlsberg Laboratory in Copenhagen. When he was working at
the Carlsberg Laboratory he studied the amount of ion concentration on proteins and the effect that it
had. In 1909 he explained the pH scale as a simple and basic way of expressing the amount of
hydrogen ions in a solution.
MATERIALS AND METHODS
In these experiments beakers, water, lemon juice, Tums, Prevacid, Pepto-Bismol, baking soda,
vinegar, stopwatches, and a pill cuter were used.
100 mL of water and 60 mL of lemon juice were added into a beaker. Different Ant-Acids were added
and left in for 60 sec. The pH before and after adding the tablet was recorded. This process was
repeated three times.
100 mL of water and 60 mL of lemon juice were added to a beaker. Different amounts of PeptoBismol were added and left in for 60 sec. The pH before and after adding the tablet was recorded.
This process was repeated three times.
100 mL of water and 60 mL of lemon juice were added to a beaker. Pepto-Bismol was added for
different times and the pH before and after were recorded. This process was repeated three times.
60 mL of lemon juice was added to a beaker. Different amounts of water were added and the pH
before and after the water was added was recorded. This process was repeated three times.
100 mL of water and 60 mL of lemon juice were added to a beaker. Different consistencies of Tums
were added and left in for 60 sec. The pH before and after were recorded. This process was
repeated three times.
100 mL of water and 60 mL of lemon juice were added to a beaker. Different amounts of baking soda
were added and left in for 60 sec. The pH before and after were recorded. This process was
repeated three times.
100 mL of water and 60 mL of lemon juice were added to a beaker. Different colors of Tums were
added and left in for 60 sec. The pH before and after were recorded. This process was repeated
three times.
50 mL of different Acid Liquids were added to a beaker. A Tum was added and left in for 60 sec. The
pH before and after were recorded. This process was repeated three times.
100 mL of water and different amounts of lemon juice were added to a beaker. A Tum was added
and left in for 60 sec. The pH before and after were recorded. This process was repeated three
times.
RESULTS AND DISCUSSION
7
6
5
pH of Before and After
4
Starting pH
3
Ending pH
2
1
0
None
Prevacid
Pepto Bismal
Tums
Type of Antacid
Figure 2. How well different ant-acids can turn an acid into a base.
Pepto-Bismol and Tums got the lowest pH of 6 and none got the highest pH of 2. Pepto-Bismol has
an active ingredient of bismuth subsalicylate. Bismuth subsalicylate is found to what makes PeptoBismol work. Bismuth subsalicylate is found in most antacids, and is a powerful antacid. In Tums
Calcium Carbonate USP is the active ingredient or what makes it work. Calcium Carbonate is also
found in many antacids. Both of these active ingredients begin working immediately. In Prevacid,
there is lansoprazole. Lansoprazole makes the capsule have a delayed reaction so there for the
capsule did not work in one min. This is why Tums and Pepto-Bismol neutralized more than
Prevacid.
7
pH Before and After
6
5
4
Starting pH
3
Ending pH
2
1
0
0
1
2
3
Amount of Pepto-Bismol
Figure 3. The amount of Pepto-Bismol that works better
4
Three tablets of Pepto-Bismol got the lowest pH of 6 and one and two tablets got the highest pH of 5.
In one and two tablets, there isn’t as much bismuth subsalicylate as in three tablets. When there is
more bismuth subsalicylate the more the pH is able to go down.
Figure 4. Three Pepto-Bismol Tablets have more bismuth subsalicylate than one tablet does.
7
The pH Before and After
6
5
4
Starting pH
3
Ending pH
2
1
0
0
20
40
60
80
100
Amount of Time (sec)
Figure 5. The amount of time that the Pepto-Bismol was in the water and lemon juice
90 sec got the lowest pH and 30 sec got the highest pH. 90 sec got the lowest pH because the
bismuth subsalicylate had more time to neutralized the acid. 30 sec got the highest pH because the
bismuth subsalicylate didn’t have much time to work. 60 sec got a lower pH than 30 sec but not as
low as 90 sec because the bismuth subsalicylate had less time neutralize the acid.
7
pH Before and After
6
5
4
Starting pH
3
Ending pH
2
1
0
0
20
40
60
80
100
120
Amount of Water (mL)
Figure 6. The amount of water added to the lemon juice
The 50 mL of water got the highest pH and the 80 mL and 100 mL got the lowest pH. The 50 mL of
water got the highest pH because the water was not able to dilute the lemon juice as much as the 100
mL of water was able to. When the water was able to dilute the lemon juice the Calcium carbonate
had an easier time making the acid to a base.
7
pH Before and After
6
5
4
Starting pH
3
Ending pH
2
1
0
Crushed
Cubed
Whole
Texture of Tums
Figure 7. The crushed and cubed Tums did better than whole
The crushed and cubed Tums got a pH of 6 and whole Tums got a pH of 5. The crushed and cubed
did better because when the tums was cubed it was able to neutralize the acidity in four places. This
meant that it was able to neutralize almost four times as much. The whole tum was only able to
neutralize the acidity in one place, so not as much as crushed or cubed. The crushed tums was able
to neutralize the acidity in many places.
8
pH Before and After
7
6
5
4
Starting pH
3
Ending pH
2
1
0
0
5
10
15
20
Amount of Baking Soda (mL)
Figure 8. The pH before and after adding the baking soda
The 15 mL baking soda and 5 mL baking soda got a pH of 7 and 1 mL of baking soda got a pH of 6.
In baking soda, the main ingredient is sodium bicarbonate. Sodium bicarbonate is the only ingredient
in baking soda. Other ingredients such as flavoring in Tums and Pepto-Bismol can help reduce the
how well the antacid can neutralize the acid.
7
pH Before and After
6
5
4
Starting pH
3
Ending pH
2
1
0
Blue
Purple
Pink
Color of Antacid
Figure 9. Blue Tums lowers the acidity more than pink and purple.
Blue got a pH of 6 and purple and pink got a pH of 5. Blue didn’t need any dyes whereas pink and
purple did. The dyes can make the antacid not work as well. This is why blue worked better than
purple and pink.
9
pH Before and After
8
7
6
5
4
Starting pH
3
Ending pH
2
1
0
Vinegar
Lemon Juice
Water
Acid Liquid
Figure 10. Tums lowers the acidity with vinegar more than lemon juice.
Water got the lowest pH of 8 but the starting pH was 7 so the tum did not have much of an effect.
Vinegar can help lower blood sugar spikes. Vinegar has a negligible amount of magnesium but still
has some. Magnesium can lower the pH temporarily, so adding the tums help lower the pH even
more. This is why the vinegar got a lower pH than lemon juice.
6
pH Before and After
5
4
3
Starting pH
2
Ending pH
1
0
0
20
40
60
80
100
Amount of Lemon Juice (mL)
Figure 11. Different amounts of lemon juice have different effects on the pH
20 mL of lemon juice got the lowest pH of 5 and 80 mL got the highest pH of 2. With 20 mL of lemon
juice, the water was able to dilute the lemon juice. Therefor the pH was low. With 80 mL of lemon
juice, the water could not dilute the lemon juice. There was so much acidity that the tums could not
work well and it did not lower the pH.
CONCLUSION
It was found that Pepto-Bismol and Tums neutralize acidity better than Prevacid. When there is
acidity in a stomach people will want to take Pepto-Bismol or Tums to help relieve pain fast. The
outcome was unsurprising because it was expected that antacids with active ingredients that are
popular in most antacids would do the best. In the future another follow up experiment would be if
either newer or older antacids work better.
CITATIONS
"Antacid." Encyclopedia Britannica. Encyclopedia Britannica Online School Edition.
Avraham, Regina. “Antacids.” The Digestive System, Chelsea House Publishers, 1989
Challoner, Jack. Acids and Bases. The Visual Dictionary of Chemistry, DK Publishing 1996
Encyclopædia Britannica, Inc., 2013. Web. 16 Jan. 2013.
Karen Vaughan “Vinegar, Muscle Cramps, Blood Sugar and Acids.” SelfGrowth. 17 Feb. 2013
Mitchel, Coleman 2012 ISP Mitchell, Coleman Cary Academy 2012
Newmark, Ann. “Acids and Bases.” Chemistry, New York: DK Publishing, 1993
“pH.”Wikipedia February 17, 2013 Web. 17 Feb. 2013