Question

Why is benzoic acid used in a soda formulation ?

Answer 1

Benzoic acid is a preservative used both as an acid and in the form of their sodium or potassium salts.

C6H5COOH + NaOH <---> C6H5COONa + H2O

Sodium Benzoate

C6H5COOH + KOH <---> C6H5COOK + H2O

Potassium Benzoate

Benzoic acid and its derivatives can only be used to preserve food at an acidic pH, being that a value of at least pH <3.6. It works efficiently against most yeasts, bacteria, fungi, mold and unwanted fermentations, sometimes used in conjunction with sulfur dioxide (SO2) or sulfites to attack microorganisms of broader spectrum.

Sodium benzoate is still present in many soft drinks like Sprite, Fanta, Sunkist, Dr Pepper and Coke Zero.

The Food and Drug Administration of the United States appoints the sodium benzoate as "generally regarded as safe." The International Programme on Chemical Safety found no adverse effects in humans at doses of 647-825 mg/kg body mass per day.