Jt 1 A Uhcl Orgo Ii Exam2.0 Questions Ch15

Front 1

1) Which of the following is an incorrect description of benzene?
A) The CCC bond angles are all equal to 120°.
B) The molecule is planar.
C) The molecule is a 6-membered ring which contains alternating single and double carbon-carbon bonds.
D) The molecule is aromatic.
E) The molecule can be drawn as a resonance hybrid of two Kekule structures.

Back 1

C) The molecule is a 6-membered ring which contains alternating single and double carbon-carbon bonds.

Front 2

2) What is the bond order of the carbon-carbon bonds in benzene?
A) 0.5
B) 1
C) 1.5
D) 2
E) 3

Back 2

C) 1.5

Front 3

3) In the molecular orbital representation of benzene, how many π molecular orbitals are present?
A) 1
B) 2
C) 4
D) 6
E) 8

Back 3

D) 6

Front 4

4) How many distinct nodal planes which are perpendicular to the molecular plane are present in the π4* orbital of benzene?
A) 0
B) 1
C) 2
D) 4
E) 5

Back 4

C) 2

Front 5

5) How many pairs of degenerate π molecular orbitals are found in benzene?
A) 6
B) 5
C) 4
D) 3
E) 2

Back 5

E) 2

Front 6

6) Which of the following undergoes SN2 reaction with sodium methoxide most rapidly?
A) PhCH2Br
B) Ph3CBr
C) PhCH2CH2Br
D) PhBr
E) PhCH2CH2CH2Br

Back 6

A) PhCH2Br

Front 7

7) Which of the following undergoes solvolysis in methanol most rapidly?
A) PhCH2Br
B) Ph3CBr
C) PhCH2CH2Br
D) PhBr
E) PhCH2CH2CH2Br

Back 7

B) Ph3CBr

Front 8

8) Aromatic molecules contain __________ π electrons.
A) no
B) 4n + 1 (with n an integer)
C) 4n + 2 (with n an integer)
D) 4n (with n an integer)
E) unpaired

Back 8

C) 4n + 2 (with n an integer)

Front 9

9) Which of the following is another name for cyclobutadiene?
A) [2]annulene
B) [4]annulene
C) [6]annulene
D) Dewar benzene
E) antibenzene

Back 9

B) [4]annulene

Front 10

11) Which of the following is the same as the tropylium ion?
A) cycloheptatrienyl cation
B) cycloheptatrienyl anion
C) cyclopentadienyl cation
D) cyclopentadienyl anion
E) cyclopropenyl anion

Back 10

A) cycloheptatrienyl cation

Front 11

16) Nitrogen's lone pair electrons occupy what type of orbital in pyridine?
A) s
B) sp
C) sp2
D) sp3
E) p

Back 11

C) sp2

Front 12

17) Which of the following is not a fused-ring heterocycle?
A) purine
B) pyrimidine
C) benzofuran
D) indole
E) quinoline

Back 12

B) pyrimidine

Front 13

18) How many distinct trichlorobenzene isomers are possible?
A) 2
B) 3
C) 4
D) 5
E) 6

Back 13

B) 3

Front 14

19) Which of the following is another accepted name for methyl phenyl ketone?
A) anisole
B) cresol
C) acetophenone
D) benzophenone
E) cresone

Back 14

C) acetophenone

Front 15

20) Which of the following is also an acceptable name for 3-nitrophenol?
A) o-nitrophenol
B) m-nitrophenol
C) p-nitrophenol
D) 3-cresol
E) hydroquinone

Back 15

B) m-nitrophenol

Front 16

21) Which of the following is also an acceptable name for 1,3,5-trimethylbenzene?
A) styrene
B) mesitylene
C) cumene
D) cymene
E) 1,3,5-xylene

Back 16

B) mesitylene

Front 17

22) Which of the following compounds has the lowest boiling point?
A) 1,2,3-trichlorobenzene
B) 1,2,4-tirchlorobenzene
C) p-dichlorobenzene
D) m-dichlorobenzene
E) o-dichlorobenzene

Back 17

C) p-dichlorobenzene

Front 18

23) Which of the following compound has the highest melting point?
A) benzene
B) toluene
C) o-dichlorobenzene
D) m-dichlorobenzene
E) p-dichlorobenzene

Back 18

E) p-dichlorobenzene

Front 19

24) In the UV-visible spectra of the following compounds, in which does lambda max appear at the highest wavelength?
A) 3-phenylpropene
B) 1-phenylpropene
C) benzene
D) n-octylbenzene
E) isopropylbenzene

Back 19

B) 1-phenylpropene

Front 20

25) In the proton NMR, in what region of the spectrum does one typically observe hydrogens bound to the aromatic ring?
A) 1.0-1.5 ppm
B) 2.0-3.0 ppm
C) 4.5-5.5 ppm
D) 7.0-8.0 ppm
E) 9.0-10.0 ppm

Back 20

D) 7.0-8.0 ppm

Front 21

26) In the carbon NMR, in what region of the spectrum does one typically observe carbons which are part of the aromatic ring?
A) -10-0 ppm
B) 40-60 ppm
C) 80-100 ppm
D) 120-150 ppm
E) 200-220 ppm

Back 21

D) 120-150 ppm

Front 22

27) Which of the following compounds has the most signals in the noise-decoupled 13C NMR spectrum?
A) o-dibromobenzene
B) m-dibromobenzene
C) p-dibromobenzene
D) 1,3,5-tribromobenzene
E) 1,2,3,4-tetrabromobenzene

Back 22

B) m-dibromobenzene

Front 23

28) In the mass spectrum of isobutylbenzene, the base peak occurs at m/z:
A) 134
B) 133
C) 119
D) 105
E) 91

Back 23

E) 91

Front 24

29) How many peaks are in the proton spin decoupled 13C NMR spectrum of p-dichlorobenzene?
A) 2
B) 3
C) 4
D) 5
E) 6

Back 24

A) 2

Front 25

30) How many peaks are in the proton spin decoupled 13C NMR spectrum of 1,3,5-trinitrobenzene?
A) 1
B) 2
C) 3
D) 4
E) 6

Back 25

B) 2

Front 26

31) How many peaks are in the proton spin decoupled 13C NMR spectrum of 1,2,3-trichlorobenzene?
A) 1
B) 2
C) 3
D) 4
E) 6

Back 26

D) 4

Front 27

13) Which of the labeled H atoms (1 -5) in the following molecule would be predicted to be the most acidic?
A) 1
B) 2
C) 3
D) 4
E) 5

Back 27

A) 1

Front 28

14) Rank the following in order of increasing pKa (from lowest to highest pKa)
A) 1 < 2 < 3
B) 3 < 2 < 1
C) 2 < 1 < 3
D) 3 < 1 < 2
E) 2 < 3 < 1

Back 28

C) 2 < 1 < 3

Front 29

15) Which sequence ranks the indicated protons in order of increasing acidity?
A) 1 < 2 < 3
B) 2 < 3 < 1
C) 3 < 1 < 2
D) 3 < 2 < 1

Back 29

D) 3 < 2 < 1

Front 30

10) Which of the following structures, if flat, would be classified as antiaromatic?

Back 30

C

Front 31

12) Which of the following structures is aromatic?

Back 31

A