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Hydrochloric Acid

Exam code: 5090
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Hydrochloric Acid

Hydrochloric Acid

  • The stomach produces several fluids which together are known as gastric juice

  • One of the fluids produced is hydrochloric acid

  • This kills bacteria in food and gives a low pH for enzymes to work in the stomach

  • Cells in the stomach lining are specially adapted to withstand the acidic conditions

How is a low pH helpful in the stomach?

  • The low pH kills bacteria in food that we have ingested as it denatures the enzymes in their cells, meaning they cannot carry out any cell reactions to maintain life

  • Pepsin, produced in the stomach, is an example of an enzyme which has a very low optimum pH - around pH 2

  • The hydrochloric acid produced in the stomach ensures that conditions in the stomach remain within the optimum range for pepsin to work at its fastest rate