1. Antacids
Chemistry Option D 2.1.

2. Antacid is a mechanism. It performs a neutralization reaction on gastric acid.
They act as a buffer, agents which adjust the pH level of a solution.
Gastric acid is a secretion produced in the stomach. It is an acidic solution (pH level 1 to 2) consists of HCl and KCl.

4. The main task of antacids is raising the pH level to reduce acidity in the stomach.
The reasons we would want that, is that the stomach would immediately dissolve itself because of the high acidity.
The gastrointestinal mucosa therefore releases a mucus, which prevents that.
This mucus contains antacids. It contains Sodium Hydrogen carbonate, NaHCO3.

5. You can develop Peptic Ulcers, which are an erosion of the mucosa
You can develop Peptic Ulcers, which are an erosion of the mucosa. When gastric HCl reaches the nerves in the mucosa, the nerves signal pain.
It may also reach ulcers in the esophagus or the duodenum.
For that to happen, you need a pylorus infection. The openings of the stomach do not close properly and gastric acids can escape.
You can also suffer from Reflux.

6. When gastric acid escapes into the esophagus, we talk of heartburn, pyrosis. It is called that way because it is described as a burning pain in the chest.
To treat all of those conditions, you can take medicaments, as a liquid or in tablet form. For example, Maalox, Alka-Seltzer or Milk of Magnesia.

7. Those medicaments work by Acid – Base reactions
Those medicaments work by Acid – Base reactions. To neutralize the gastric acid, bases are used. The most popular, are Aluminium and Magnesium compounds and Sodium Hydrogen carbonate.
For example, Maalox is made up out of a compound of Al(OH)3 and Mg(OH)2.

8. Compound Chem. formula Chem. reaction Al(OH)3 CaCO3 MgCO3 Mg(OH)2
Aluminium hydroxide
Al(OH)3
Al(OH)3 + 3HCl  AlCl3 + 3H2O
Calcium carbonate
CaCO3
CaCO3 + 2HCl  CaCl2 + H2O + CO2
Magnesium carbonate
MgCO3
MgCO3 + 2HCl  MgCl2 + H2O + CO2
Magnesium hydroxide
Mg(OH)2
Mg(OH) + 2HCl  MgCl2 + 2H2O
Sodium bicarbonate
NaHCO3
NaHCO3 + HCl  NaCl + H2O + CO2

9. Common side effects of those drugs are problems in digestion
Common side effects of those drugs are problems in digestion. For example, diarrhea, constipation or flatulence.
More serious side effects can include kidney damage or internal bleedings.
Problems of a higher pH level of the gastric acid are an impaired ability to digest and absorb certain nutrition. Since the low pH level of the gastric acid kills bacteria, antacids increase the risk of infections.