Benzoic acid

December 21, 2020
Use me to make a holiday snow globe.
What molecule am I?

Benzoic acid, the simplest benzene-based carboxylic acid, has been known since the 16th century. One of its discoverers was the legendary clairvoyant Nostradamus. Its most common natural source is gum benzoin, a resin found in the bark of trees of the genus Styrax.

Most benzoic acid produced today is synthetic. Its first industrial synthesis was the hydrolysis of benzotrichloride to calcium benzoate, followed by acidification. This method has been completely displaced by the air oxidation of toluene, which avoids the problem of product contamination with chlorinated byproducts.

Many processed foods contain benzoic acid or one of its salts as a preservative. The acid inhibits the growth of bacteria, molds, and yeasts; it works best when the food has an acidic pH value. Benzoic acid also is often found in topical antifungal preparations.

Why is benzoic acid our December holiday molecule? It’s the white stuff predominantly used to mimic snowflakes in snow globes. For a holiday project, you might want to create your own snow globe by using the procedures developed by Steve Spangler Science or Science with Mrs. Pittenger. Benzoic acid is readily available from Amazon and other vendors.

Benzoic acid hazard information

Hazard class* Hazard statement
Skin corrosion/irritation, category 2 H315—Causes skin irritation  Chemical Safety Warning
Serious eye  damage/eye irritation, category 1 H318—Causes serious eye damage  Chemical Safety Warning
Specific target organ toxicity (lungs), repeated exposure, category 1 H372—Causes damage to organs (lungs) through prolonged or repeated exposure Chemical Safety Warning
Hazardous to the aquatic environment, acute hazard, category 3

H402—Harmful to aquatic life

*Globally Harmonized System of Classification and Labeling of Chemicals.  
Explanation of pictograms.

This molecule was suggested by a reader. We present almost all of the molecules suggested by our readers. If you have a molecule you would like us to consider, please send an e-mail to motw@acs.org. And thank you for your interest in Molecule of the Week! —Ed.

Benzoic acid fast facts

CAS Reg. No. 65-85-0
SciFinder
nomenclature
Benzoic acid
Empirical formula C7H6O2
Molar mass 122.12 g/mol
Appearance White crystals
Melting point 122 ºC 
Water solubility 3.4 g/L
Chemical Abstract Service - a division of ACS

Learn more about this molecule from CAS, the most authoritative and comprehensive source for chemical information.

Molecule of the Week needs your suggestions!

If your favorite molecule is not in our archive, please send an email to motw@acs.org. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!

Stay Ahead of the Chemistry Curve

Learn how ACS can help you stay ahead in the world of chemistry.