Organic Chemistry 9th Edition By Francis Carey -Test Bank

7. How many isomeric tribromobenzenes are possible?
A) one B) two C) three D) four
Ans: C
8. Which of the following is not true concerning the structure of benzene?
A) All C-C-C bond angles are exactly 120o
.
B) The carbon-carbon bonds rapidly alternate between single and double bonds.
C) The six hydrogens are equivalent.
D) The π bonds are completely conjugated.
Ans: B

10. The total number of resonance forms of the cyclopentadienide anion, C5H5¯ , is
A) two. B) three. C) four. D) five.
Ans: D

14. Which of the following reacts at the fastest rate when heated with N-bromosuccinimide
(NBS) and benzoyl peroxide in carbon tetrachloride at 80oC?
A) toluene C) isopropylbenzene (cumene)
B) ethylbenzene D) tert-butylbenzene
Ans: C
15. The Birch reduction of benzene with sodium in NH3/CH3OH goes by a four-step
mechanism. The first step is the
A) transfer of a proton from CH3OH to benzene.
B) transfer of an electron from Na to benzene.
C) transfer of an electron from benzene to NH3.
D) transfer of a hydride ion, H¯ , from NH3 to benzene.
Ans: B

18. Side chain oxidations of alkylbenzenes with Na2Cr2O7 and H2SO4/H2O will not work if
the alkyl side chain has
A) only one carbon. C) benzylic hydrogens.
B) four or more carbons. D) no benzylic hydrogens.
Ans: D
19. Which of the following are consistent with the requirements for aromaticity?
I. A system with delocalized π electrons in a ring.
II. 4n π electrons in the ring.
III. All the ring atoms must be carbons.
IV. (4n + 2) π electrons in the ring.
A) I and II B) I and IV C) I, II, and III D) I, III, and IV
Ans: B
20. Cyclopentadiene is unusually acidic for a hydrocarbon. Why?
A) Cyclopentadiene is aromatic.
B) The conjugate base of cyclopentadiene is aromatic.
C) Cyclopentadiene is an unstable diradical.
D) The conjugate base of cyclopentadiene is an unstable diradical.
Ans: B

27. A compound X, C8H10, is oxidized to benzoic acid with potassium dichromate, K2Cr2O7,
in sulfuric acid. What is compound X?
A) para-xylene B) propylbenzene C) styrene D) ethylbenzene
Ans: D
28. Acid-catalyzed dehydration of cis-2-phenylcyclopentanol gives
A) 1-phenylcyclopentene. C) 4-phenylcyclopentene.
B) phenylcyclopentane. D) 1-phenylcyclopentanol.
Ans: A

31. Select the best method to convert styrene, C6H5CH=CH2, to 2-phenylethanol with
minimal by-product formation.
A) H2O, H2SO4
B) (1) BH3-THF (2) H2O2, NaOH
C) (1) HBr (2) KOH, H2O
D) (1) HBr, peroxides (2) NaOH, H2O
Ans: B
32. Which of the following would be a correct number of π electrons for a planar,
monocyclic, completely conjugated polyene to be aromatic?
A) 3 B) 8 C) 18 D) 24
Ans: C