Benzoic Acid (benzenecarboxilic acid)

Carboxylic Acid based on a six-carbon aromatic resonance structure. Colourless liquid with a sharp, unpleasant odour. Low solubility (0.4g/100g H2O at 25 degrees C, althout this rises to 6.8g at 95 degrees. Relatively high melting and boiling points.
Benzoic acid is one of the weaker carboxylic acids, with a pKa value of 4.18.

It can be prepared by oxidising the side chain on an aromatic ring, for example by adding potassium permanganate to tolulene, C6H5CH3.