Question

Benzene is often produced as a by-product during the synthesis of phenylmagnesium bromide. how can its formation be explained? Write a balanced chemical equation for the formation of benzene.

Answer 1

This question usually asks why biphenyl is formed?

Benzene is formed when the reaction is quenched as the reaction is usually carried out with excess Grignard Reagent.

PhMgBr + H2O -> PhH + Mg2+ + HO- +Br-

The inorganics form a whitish sludge initially and then the reaction is usually acidified to get the magnesium salts into solution.