Antacids Acid Base Chemistry

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Antacids

12.2 Antacids State and Explain how excess acidity in the stomach can be reduced by the use of different bases. Antacids: bases, metal oxides, hydroxides, carbonates, hydrogen carbonates Reacts with stomach acid (excess) to adjust the stomach pH to the desired level

Purpose of HCl in the stomach To suppress growth of harmful bacteria To help in digestion by hydrolyzing proteins to amino acids Normal pH of stomach acid ~ 1.2 – 0.3 range, Stress also produces more acid

Role of antacids Neutralizes the excess acids and relives the discomfort Excess acid can cause ulcers

Examples: Over the Counter Al(OH)3 Mg(OH)2 CaCO3 NaHCO3

Alginates Antacids are combined with Alginates extracted from brown sea weeds produces neutralizing layer that prevents acid reflux / acid entering into oesophagus

Dimethicone / Antifoaming agent Are added to antacids to reduce the surface tension of gas bubbles And produce de-foaming action

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Active ingredients of some commercial antacids Tums: CaCO3 MgCO3 Mg Si3O8 For the treatment of gastritis and of ulcers Rolaids : AlNa(OH)2CO3 Malox : Al(OH)3 Mg(OH)2 Alka Seltzer : NaHCO3 , citric acid, aspirin

Alka Seltzer : NaHCO3 , citric acid, aspirin

Active ingredients of some commercial antacids Milk of Magnesia : Mg(OH)2 or MgO/Mg(OH)2 mixture Amphogel Al(OH)3 Di-Gel : CaCO3

Action of Antacids Alkalosis: high doses of antacids basic stomach Mg2Si3O8 + 4 HCl 3 SiO2(s) 2 H2O (l) + 2 MgCl2(aq) Write the reactions for rest of the antacids Alkalosis: high doses of antacids basic stomach Other problems: body produces more acids