By referring to the formation of $\sigma$ and $\pi$ bonds, describe and explain the shape of a benzene molecule, $\text{C}_6\text{H}_6$.
2,3-dimethylphenylamine can be made from 1,2-dimethylbenzene in two steps, as shown. Step 1 is catalysed by $\text{H}_2\text{SO}_4$. Write an equation to show how $\text{H}_2\text{SO}_4$ produces the electrophile in step 1.
Draw the mechanism for the reaction between this electrophile and 1,2-dimethylbenzene to form $M$. Include all relevant curly arrows and charges.
Write an equation to show how the $\text{H}_2\text{SO}_4$ catalyst is reformed.
For step 2, suggest the reagents and conditions and name the type of reaction.
Deduce the molecular formula for mefenamic acid.
Name the functional groups, other than the benzene ring, in mefenamic acid.
Calculate the maximum mass of mefenamic acid that could be made from $5.00\,\text{g}$ of 2,3-dimethylphenylamine in this reaction. Give your answer to three significant figures.
Use this information and your knowledge of cation stability to suggest why the $\text{CH}_3$ group directs incoming electrophiles to the 2- and 4-positions rather than the 3-position.