This organic chemistry lab video describes an experiment where phenyl Grignard reagent is formed from bromobenzene and magnesium metal and then subsequently treated with solid carbon dioxide (CO2) and aqueous acid to synthesize benzoic acid. This product is then separated from a biphenyl impurity using a series of acid-base extractions. The resulting purified benzoic acid is then characterized by IR spectroscopy and melting point analysis. This is the third video in the series and covers the Grignard reaction of phenyl magnesium bromide with CO2, workup and purification of the benzoic acid product, and characterization by melting point and IR spectroscopy.