(a)[5]
L-DOPA and vanillin both include an aromatic benzene ring. Describe, with the aid of a diagram, the bonding and shape of a benzene molecule, $\text{C}_6\text{H}_6$.
(b)[7]
A student carried out some reactions on samples of L-DOPA and vanillin using reagents $X$, $Y$ and $Z$. Reagent $X$ reacted with L-DOPA and with vanillin. Reagent $Y$ reacted with L-DOPA but not with vanillin. Reagent $Z$ reacted with vanillin but not with L-DOPA. Assume that the $\text{CH}_3\text{O}-$ group in vanillin does not react. Suggest possible identities of reagents $X$, $Y$ and $Z$ and give the structures of the organic products that were formed.