Question 1

Which of the following statements best explains why all C—C bond lengths in benzene are equal?

Accepted Answer

Benzene undergoes resonance, resulting in delocalization of electrons and equal bond lengths.

Question 2

According to Hückel’s Rule, how many $	ext{π}$ electrons must a molecule have to be aromatic?

Accepted Answer

$4n+2$ where $n$ is an integer

Question 3

Which of the following compounds is NOT aromatic?

Accepted Answer

Cyclobutadiene

Question 4

What is the major product when benzoic acid ($\mathrm{C_6H_5CO_2H}$) is heated with calcium oxide ($\mathrm{CaO}$)?

Accepted Answer

$\mathrm{C_6H_6}$ (benzene)

Question 5

Which of the following is a correct resonance structure for the benzylic carbocation?

Accepted Answer

A structure where the positive charge is delocalized onto the ortho and para positions of the benzene ring.

Question 6

Which of the following conditions favors an $\mathrm{S_N1}$ reaction for benzylic halides?

Accepted Answer

Tertiary alkyl halide and non-anionic base

Question 7

Which reagent can oxidize a benzylic carbon to a carboxylic acid in the laboratory?

Accepted Answer

$\mathrm{KMnO_4}$

Question 8

Which of the following is a polyaromatic hydrocarbon?

Accepted Answer

Naphthalene

Question 9

What is the product of the Birch reduction of toluene ($\mathrm{C_6H_5CH_3}$) using $\mathrm{Na}$, $\mathrm{NH_3}$, and $\mathrm{CH_3OH}$?

Accepted Answer

1,4-cyclohexadiene with a methyl group on the carbon of the alkene

Question 10

Which of the following is the correct nomenclature for a benzene ring with methyl groups at positions 1 and 3?

Accepted Answer

m-xylene

Question 11

Which of the following heterocyclic compounds is aromatic?

Accepted Answer

Furan

Question 12

What is the major product when styrene reacts with HBr in the presence of peroxides?

Accepted Answer

1-bromo-2-phenylethane (Anti-Markovnikov addition)

Question 13

Which of the following is true about the molecular orbitals in benzene?

Accepted Answer

All six $\mathrm{π}$ electrons occupy bonding molecular orbitals, resulting in aromatic stability.

Question 14

Which of the following is the correct systematic name for acetophenone?

Accepted Answer

Methyl phenyl ketone

Question 15

Why does hydrolysis of 2-chloro-2-phenylpropane occur much faster than 2-chloro-2-methylpropane?

Accepted Answer

The benzylic carbocation is stabilized by resonance with the aromatic ring.

Question 16

Which of the following is NOT a derivative of benzene?

Accepted Answer

Cyclohexane

Question 17

Which of the following conditions favors an $\mathrm{S_N2}$ reaction for benzylic halides?

Accepted Answer

Primary alkyl halide and strong nucleophile in polar aprotic solvent

Question 18

Which of the following is the correct product of the free radical halogenation of toluene with $\mathrm{Cl_2}$ and light?

Accepted Answer

Benzyl chloride ($\mathrm{C_6H_5CH_2Cl}$)

Question 19

Which of the following is the correct structure for 2-phenyl-1-ethanol?

Accepted Answer

$\mathrm{PhCH_2CH_2OH}$ (where Ph = phenyl group)

Question 20

Which of the following is true about the oxidation of benzene with $\mathrm{Na_2Cr_2O_7}$ and $\mathrm{H_2SO_4}$?

Accepted Answer

No reaction occurs because benzene lacks a benzylic hydrogen.

Arenes and Aromaticity: Structure, Properties, and Reactions of Benzene and Its Derivatives

Study Guide - Practice Questions