Bullrich Salt against an Excess of Gastric Acid

Demonstration Experiment on Video

Bullrich Salt against an Excess of Gastric Acid

Objectives: Neutralization, Bicarbonate as an Antacid

Peter Keusch

German version

Supermarket products:
red cabbage juice
vinegar essence
Bullrich Salt Powder - medicament against heartburn, active component: sodium bicarbonate

Glass wares:
3 vonical measures, graduated, 350 mL
Petris dish d = 9 cm
2 snap-cap vials 20 mL
2 glass stirring rods

Experimental procedure:

150 mL of water and 3 mL of concentrated red cabbage juice are placed in each of three conical measures. Two of the three solutions are mixed with 10 mL of vinegar essence. The third solution serves as reference solution. Three spatula full of Bullrich Salt are added to one of the two acidified solutions.

Result:

The purple cabbage juice turns red when it is acidified. When Bullrich Salt is added the color changes from red to purple to blue while foaming.

Videoclip (Download RealPlayer .rm file)

Discussion and background:

The color change of the indicator shows that the vinegar has been neutralized by Bullrich Salt. The release of carbon dioxide causes the solutions to foam.

Gastric juice contains hydrochloric acid and an enzyme called pepsin, by which the proteins in the food are converted into polypeptides. The gastric juice is highly acidic with a pH of about 2. The HCl in the gastric juice serves to kill off micro-organisms and also to denature proteins. Furthermore it creates the right pH for the enzymes to work efficiently. This acid is so strong that it has the capacity to dissolve not only the food but also the stomach walls. The stomach walls are protected by the epithelial cells, which produce and secrete a bicarbonate-rich solution that coats the mucosa. Secreted bicarbonate neutralizes the stomach acid, and raises the pH in the small intestine to just slightly acidic (about 5.5), which is the chemical environment in which the pancreatic enzymes work best.
Stress situations, alcohol, nicotine, caffeine, fat-rich or spicy foods and stomach damaging drugs are responsible that this protection mechanism does not work.

Since decades bicarbonate containing drugs such as Bullrich Salt are used to relieve heartburn. Bicarbonate is an excellent acid buffer - but the effect usually lasts only a short time. The stomach also releases carbon dioxide when stomach acid and bicarbonate mix. This leads to swelling of the stomach. Bicarbonate tends to decrease stomach acidity too much.The rapid neutralization of the gastric acid stimulates the production of more hydrochloric acid.

Also aluminium hydroxide, magnesium carbonate and magnesium hydroxide are commonly used as antacids in a variety of preparations. They are indicated for acute gastric irritation indigestion, providing rapid relief by neutralising excess acid in the stomach. Their side-effects make them unsuitable for long-term use.

Drugs known as histamine receptor antagonists (H2 blockers) work indirectly by blocking the histamine receptors on the acid producing cells in the stomach, blocking one of the mechanisms by which acid is secreted.

Reference:
G. Schwedt: Experimente mit Supermarktprodukten, Wiley-VCH-Verlag, Weinheim (Germany) 2001

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