Chapter 5 - Aromatic Compounds
1. What is the IUPAC name of the following compound?
a. | 2,4-dibromotoluene |
b. | 2,4-dibromophenol |
c. | 2,4-dibromoaniline |
d. | 4,6-dibromophenol |
ANS: B
2. What is the IUPAC name of the following compound?
a. | 3-bromo-4-nitrobenzaldehyde |
b. | 2-bromo-1-nitro-4-benzoic acid |
c. | 3-bromo-4-nitroacetophenone |
d. | 3-bromo-4-nitrobenzoic acid |
ANS: D
3. Which of the following compounds is aromatic?
a. | ethane |
b. | cyclobuta-1,3-diene |
c. | benzene |
d. | cycloocta-1,3,5,7-tetraene |
ANS: C
4. What is the major organic product obtained from the following reaction?
a. | c. | ||
b. | d. |
ANS: C
5. Which of the following undergoes the most rapid bromination upon treatment with Br2/FeBr3?
a. | benzene |
b. | nitrobenzene |
c. | bromobenzene |
d. | benzaldehyde |
ANS: A
6. Which of the following undergoes the most rapid acylation upon treatment with acetyl chloride and AlCl3?
a. | benzene |
b. | toluene |
c. | chlorobenzene |
d. | 1,4-dichlorobenzene |
ANS: B
7. Which of the following sets of substituents are all o/p-directing in electrophilic aromatic substitution reactions?
a. | Cl, CH3, CN |
b. | Br, OH, COCH3 |
c. | Cl, OH, CH3 |
d. | CN, NO2, COCH3 |
ANS: C
8. Which of the following sets of substituents are all deactivating groups in electrophilic aromatic substitution reactions?
a. | Cl, CN, NO2 |
b. | Cl, NH2, CH3 |
c. | CH3, OCH3, COCH3 |
d. | CH3, NH2, OCH3 |
ANS: A
9. What is the major organic product obtained from the following reaction?
a. | c. | ||
b. | d. |
ANS: A
10. An accurate description of the structure of benzene is:
a. | The bonds are quickly moving around the ring. |
b. | There are two distinct structures that are in equilibrium. |
c. | All the carboncarbon bonds are equal in length. |
d. | There are distinct single and double bonds. |
e. | Some bonds are longer than others. |
ANS: C
11. Which of the following is a correct statement regarding electrophilic aromatic substitution?
a. | The carbocation intermediate will lose a proton to regain aromaticity, usually from a position other than the site of electrophilic attack. |
b. | Formation of the carbocation intermediate has a high activation barrier due to loss of aromaticity. |
c. | The carbocation intermediate has several resonance structures and is negatively charged. |
d. | Re-formation of the aromatic ring has a low activation barrier and therefore occurs slowly. |
e. | Many suitable electrophiles are unreactive and can be stored for long periods of time prior to use. |
ANS: B
12. Place the following in order of reactivity towards electrophilic aromatic substitution.
a. | I > II > III > IV |
b. | I > II > IV > III |
c. | II > I > III > IV |
d. | II > I > IV > III |
e. | III > IV > II > I |
ANS: B
13. What is the correct assignment of the names of the following aromatic compounds?
a. | 1 = anisole; 2 = furan; 3 = pyrimidine |
b. | 1 = aniline; 2 = pyrrole; 3 = pyridine |
c. | 1 = anisole; 2 = pyridine; 3 = pyrrole |
d. | 1 = aniline; 2 = imidazole; 3 = pyridine |
ANS: B
14. Draw the structure of 4-bromo-2-fluorotoluene.
ANS:
15. Draw the resonance structures for acenaphthene.
ANS:
16. Circle the compound(s) in the following set that will undergo both substitution and addition when treated with Br2.
ANS:
17. Consider the production of 1-bromo-4-nitrobenzene:
a) | Explain why Pathway A for the production of 1-bromo-4-nitrobenzene produces a higher yield of the product. |
b) | If reaction Pathway A is carried out at high temperatures, a trisubstituted product forms. Draw the structure of the product and explain why it forms. |
ANS:
a) | Bromine is an o/p-director while the nitro group is a meta director. |
b) | |
Bromine is an o/p-director while the nitro group is a meta director. Both groups direct the second NO2 to the same position--the position that is ortho to Br and is also meta to NO2. |
18. Consider the following sequence of reactions:
a) | What is the major organic product obtained from the sequence of reactions? | |||
a. | b. | c. | d. | |
b) | If KMnO4 had been replaced by Na2Cr2O7, what would be the final product of the reaction? |
ANS:
a) | c |
b) | No change, the product would still be the oxidation of the alkyl side chain. |
19. Draw the major product of the following reaction:
ANS:
20. Consider the following compound:
a) | Provide the correct IUPAC name for the compound. |
b) | Draw and name the other isomeric nitrotoluenes. |
ANS:
a) | m-nitrotoluene or 1-methyl-3-nitrobenzene | ||
b) | p-nitrotoluene | o-nitrotoluene | |
1,4-nitrotoluene | 1,2-nitrotoluene | ||
Instructions: Consider the reaction below to answer the following question(s).
21. Refer to instructions. The nucleophile in the reaction is indicated by letter _____.
ANS: A
22. Refer to instructions. The Lewis acid catalyst in the reaction is indicated by letter _____.
ANS: C
23. Refer to instructions. This reaction proceeds _____________ (faster or slower) than benzene.
ANS: slower
24. Refer to instructions. Draw the structure of product D.
ANS:
25. Which of the following heterocycles is aromatic?
a. | |
b. | |
c. | |
d. |
ANS: A, B, D
26. Circle the aromatic portion of the following molecule:
ANS:
27. Circle the aromatic portion of the following molecule:
ANS:
28. Draw the structure of m-fluoronitrobenzene.
ANS:
29. Draw the structure of p-bromoaniline.
ANS:
30. Draw the structure of o-hydroxybenzoic acid.
ANS:
31. Draw the structure of 3,5-dimethylphenol.
ANS:
32. Draw the structure of p-chlorobenzaldehyde.
ANS:
Instructions: Provide the IUPAC name for each of the following compounds.
33. IUPAC Name:
ANS: m-nitrotoluene
34. IUPAC Name:
ANS: isopropylbenzene or cumene
35. IUPAC Name:
ANS: cis-1-methyl-3-phenylcyclohexane
36. IUPAC Name:
ANS: 2,4-diaminotoluene
37. IUPAC Name:
ANS:
(E)-2,3-diphenyl-2-butene
Instructions:
Consider the Friedel-Crafts alkylation reaction below to answer the following questions:
38. Draw the structure of the electrophile in this reaction.
ANS:
39. What is the role of the AlCl3 in the reaction?
ANS:
The AlCl3 is a Lewis acid catalyst that assists in the ionization of the alkyl halide to give the carbocation electrophile.
40. On the structures provided below, draw arrows showing the complete stepwise mechanism for this reaction.
ANS:
Instructions:
Given the major organic product(s) of each of the following reactions. If no reaction is predicted, write "N.R."
41. Write the product:
ANS:
42. Write the product:
ANS:
43. Write the product:
ANS:
44. Write the product:
ANS:
45. Write the product:
ANS:
46. Write the product:
ANS:
47. Write the product:
ANS:
48. Write the product:
ANS:
Instructions:
Choose the best reagent(s) from the list provided below for carrying out the following conversions. Place the letter of the reagent in the box beside the reaction number over the arrow. There is only one answer for each reaction.
a. KMnO4, H3O+
b. Br2, FeBr3
c. Cl2, FeCl3
d. CH3Cl, AlCl3
e. HNO3, H2SO4
49. Choose the best reagents:
ANS:
50. Choose the best reagents:
ANS:
Instructions:
Starting with benzene or toluene, how would you synthesize these compounds? Assume ortho and para isomers can be separated.
51. Synthesize:
ANS:
52. Synthesize
ANS:
