Give the structure of each of the following aromatic hydrocarbons. $$ \begin{array}{ll}{\text { a. } o \text { -ethyltoluene }} & {\text { c. } m \text { -diethylbenzene }} \\ {\text { b. } p \text { -di-tert-butylbenzene }} & {\text { d. } 1 \text { -phenyl-2-butene }}\end{array} $$

Start by drawing a hexagon to represent the six carbon atoms that form the backbone of the aromatic hydrocarbon. Place three alternating double bonds and three single bonds along the edges of the hexagon.

For each of the compounds, we will add the substituents (carbon chains) to the benzene ring according to the given name of the hydrocarbon. a. o-ethyltoluene: "o" stands for "ortho" which means that the two substituents are on adjacent carbon atoms. In this case, we have an ethyl group (-C2H5) and a methyl group (-CH3) since toluene is a benzene ring with a methyl group attached. Attach these groups to the benzene ring on adjacent carbon atoms. b. p-di-tert-butylbenzene: "p" stands for "para" which means that the two substituents are on opposite sides of the benzene ring. Here, we have two tert-butyl groups (-C(CH3)3). Place these groups on opposite carbon atoms in the benzene ring. c. m-diethylbenzene: "m" stands for "meta" which means that the two substituents are separated by one carbon atom. In this case, we have two ethyl groups (-C2H5). Attach these groups to the benzene ring with one carbon atom in between. d. 1-phenyl-2-butene: This molecule consists of a benzene ring attached to a 4-carbon chain with a double bond between the second and third carbon. First, draw a 4-carbon chain with a double bond between the second and third carbon. Next, attach the benzene ring to the first carbon atom of the chain.

a. o-ethyltoluene: CH3 | C2H5-C1-C6H4-C2 | CH3 b. p-di-tert-butylbenzene: C(CH3)3-C1-C6H4-C4-C(CH3)3 c. m-diethylbenzene: C2H5-C1-C6H4-C3-C2H5 d. 1-phenyl-2-butene: C1-C6H5-C2=CH-CH3