Some biphenyl (C6H5-C6H5) is produced as a by-product in the synthesis of benzoic acid. Where does it come from? This question has to deal with the Grignard reaction.

Question

Can anyone help me with this please?

Answer 1

This may be close, although not exactly, what you are looking for.
http://en.wikipedia.org/wiki/Wurtz_reaction

Answer 2

Mg (s) + 2C6H5-Br (l) = C6H5-C6H5 + Br-Mg-Br

Mg + C6H5-Br = C6H5-Br-Mg
C6H5-Br-Mg = Grignard

C6H5-C6H5 is a by-product from synthesis of reagenset