Why is Sodium in Soda

Sodium carbonate (soda)Auxiliary materialsSaltsBases Sodium Carbonate (Soda, Na2CO3) is the disodium salt of carbonic acid. It is a white, crystalline and strongly hygroscopic powder and is easily soluble in water. Sodium carbonate is a relatively strong base and is used in pharmacy as an auxiliary, for example as an acid regulator. It is also used as a cleaning agent and for the preparation of lye pastries. Due to its basicity, it can cause serious eye irritation if it comes into contact with the eyes.

Synonym: Natrii carbonas, Natrii carbonas anhydricusPhEur, Natrii carbonas monohydricusPhEur, Natrii carbonas decahydricusPhEur, Sodium carbonate, E 500i


Sodium carbonate or soda is available as a basic substance in pharmacies and drug stores. The different products differ in the bound crystal water. It is contained in medicinal products as an excipient.

Structure and properties

Sodium carbonate (Na2CO3, Mr = 105,988 g / mol) is a white, crystalline, odorless and strongly hygroscopic powder that is easily soluble in water. It dissolves even better in warm or hot water. It is the disodium salt of carbonic acid and is therefore also called disodium carbonate. Anhydrous sodium carbonate has a high melting point of 851 ° C to 854 ° C. Sodium carbonate occurs naturally as a mineral and is synthetically produced using the Solvay method.

The pharmacopoeia knows three qualities that differ in the bound crystal water:

Incidentally, sodium carbonate can be obtained from sodium hydrogen carbonate by heating. This creates the gas carbon dioxide and water:

This experiment is also exciting because gas bubbles form in the powder.


Sodium carbonate is a relatively strong base (pKb = 3.67). Adding 4 g to 1 L of water results in a solution with a pH of over 11. It is milder than the caustic sodium hydroxide (NaOH). The effects are based on the release of the hydroxide ion in aqueous solution. Sodium carbonate also has antiseptic properties.

With an acid, carbon dioxide (CO2):

application areas

Small selection:

  • As a pharmaceutical excipient, e.g. as an acidity regulator and in nicotine chewing gum.
  • As a cleaning agent in the household, e.g. for glasses, the oven and the drain.
  • For the preparation of lye pastries.
unwanted effects

Due to its basicity, sodium carbonate can cause serious eye irritation. In the event of accidental contact, rinse with running water for at least 10 minutes. Remove contact lenses carefully and continue rinsing. The corresponding precautionary measures can be found in the safety data sheet.

see also literature
  • Medicinal product information (CH)
  • European Pharmacopoeia PhEur
  • Specialist literature
  • Encyclopedias of chemistry and pharmacy
  • Safety data sheet

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

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This article was last changed on December 3, 2019.
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