Ch16-ques-2013 3d491x
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Chapter Sixteen Topic: Introduction to NMR Section: 16.1 Difficulty Level: Easy 1. Which of the following can not be probed by an NMR spectrometer? A) B) C) D) E)
nucleus with odd number of protons & odd number of neutrons nucleus with odd number of protons &even number of neutrons nucleus with even number of protons & odd number of neutrons nucleus with even number of protons & even number of neutrons none of these Ans: D
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Easy 2. How many nuclear spin states are possible for the 1H nucleus? A) B) C) D) E)
1 2 4 5 none of these Ans: B
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Easy 3. Which of the following electromagnetic radiation is used in NMR spectroscopy? A) B) C) D) E)
UV IR visible γ-rays radio wave Ans: E
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Medium
4. _______ protons experience a net magnetic field strength that is smaller than the applied magnetic field. A) deshielded B) shielded C) paramagnetic D) diamagnetic E) none of these Ans: B Topic: Introduction to NMR Section: 16.1 Difficulty Level: Medium 5. _______ protons experience a net magnetic field strength that is higher than the applied magnetic field. A) deshielded B) shielded C) paramagnetic D) diamagnetic E) none of these Ans: A Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Medium 6. Which of the following is true about the relationship between the energy gap (ΔE) between the spin states for a 1H nucleus and the strength of the external magnetic field?. A) they are inversely proportional B) they are directly proportional C) there is no relationship D) the magnetic field is slightly less E) none of these Ans: B Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Medium
7. The strength of the magnetic field is a determining factor for the range of _______that must be used for NMR spectrometer. A) temperature B) frequencies C) tesla D) spin states D) none of these Ans: B Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Easy 8. Which of the following is not a common solvent used for acquiring a 1H NMR spectrum? A) CDCl3 B) CCl4 C) CD3CN D) CH3OH E) D2O Ans: D Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 9. Which of the following is true about the number of signals in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different kinds of protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: C
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy
10. Which of the following is true about the location of signals in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: D
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 11. Which of the following is true about the area under each signal in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: E
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 12. Which of the following is true about the shape of the signal in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: A
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
13. Which of the following type of protons are chemically non equivalent? A) B) C) D) E)
homotopic enantiotopic diastereotopic A&B B&C Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 14. Which of the following type of protons are chemically equivalent? A) B) C) D) E)
homotopic enantiotopic diastereotopic A&B B&C Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Easy 15. Protons Ha and Hb in the following compound are _________. Ha
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: A
Topic: Number of signals Section: 16.4 Difficulty Level: Easy
Hb
16. Protons Ha and Hb in the following compound are _________. Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: B
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 17. Protons Ha and Hb in the following compound are _________. Ha
Hb
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
18. Protons Ha and Hb in the following compound are _________. Br
H
Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 19. Protons Ha and Hb in the following compound are _________. OH
Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
20. Protons Ha and Hb in the following compound are _________. Ha Hb
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Easy 21. How many signals would you expect to find in the 1H NMR spectrum of CH3OCH2CH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: C Topic: Number of signals Section: 16.4 Difficulty Level: Easy 22. How many signals would you expect to find in the 1H NMR spectrum of CH3OCH2CH2OCH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: B Topic: Number of signals Section: 16.4 Difficulty Level: Easy
23. How many signals would you expect to find in the 1H NMR spectrum of (CH3)2CHCH2CH2CH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: E Topic: Number of signals Section: 16.4 Difficulty Level: Medium 24. How many signals would you expect to find in the 1H NMR spectrum of HOCH2CH2CH2CH2OH? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: C Topic: Number of signals Section: 16.4 Difficulty Level: Medium 25. How many signals would you expect to find in the 1H NMR spectrum of the following compound?
A) B) C) D) E)
4 5 6 7 8 Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
26. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
A) B) C) D) E)
4 5 6 7 8 Ans: B
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 27. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
A) B) C) D) E)
OH
4 5 6 7 9 Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 28. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
Ans: 4
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 29. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O Cl
Ans: 6 Topic: Number of signals Section: 16.4 Difficulty Level: Medium 30. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
Ans: 3 Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 31. The 1H NMR spectrum of bromoethane shows a signal at 3.5ppm when the spectrum is recorded using a 60-MHz spectrometer. Where do you expect to see the signal if a 300MHz instrument is used instead? A) 3.5 ppm B) 7.5 ppm C) 6.8 ppm D) 5.8 ppm E) none of these Ans: A Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 32. ______is used as a reference for recording NMR spectroscopy and is assigned a chemical shift value of zero. Ans: Tetramethylsilane (TMS)/ (CH3)4Si
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 33. Which of the indicated protons in the following compound would appear most downfield in the 1H NMR spectrum? III
OH
I II
A) B) C) D)
IV
I II III IV Ans: D
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 34. Which of the indicated protons in the following compound would appear most downfield in the 1H NMR spectrum? II
III
H
H
H
C
C
C
I
H
H
IV CH3
F
V
A) B) C) D) E)
I II III IV V Ans: E
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard
H
35. Which of the indicated protons in the following compound would appear most upfield in the 1H NMR spectrum? II
O
IV
O
O
A) B) C) D) E)
I II III IV I & III Ans: A
F
I
III
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 36. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
O
HO
II
A) B) C) D) E)
III
I=3.7 ppm, II=2.7 ppm, III=1.9 ppm I=3.7 ppm, II=2.2 ppm, III=1.9 ppm I=3.9 ppm, II=2.7 ppm, III=1.9 ppm I=3.9 ppm, II=2.2 ppm, III=2.4 ppm none of these Ans: C
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy
37. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? II
O O
I
A) B) C) D) E)
III
IV
I=3.9 ppm, II=4.2 ppm, III=2.2 ppm, IV=3.4 ppm I=3.4 ppm, II=2.2 ppm, III=2.2 ppm, IV=3.4 ppm I=3.4 ppm, II=2.2 ppm, III=4.2 ppm, IV=3.4 ppm I=3.4 ppm, II=4.2 ppm, III=4.2 ppm, IV=3.4 ppm none of these Ans: D
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 38. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
III
O
O
A) B) C) D) E)
II
IV
I=0.9 ppm, II=1.7 ppm, III=3.9 ppm, IV=2.4 ppm I=0.9 ppm, II=1.2 ppm, III=3.7 ppm, IV=1.9 ppm I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=2.4 ppm I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=1.9 ppm none of these Ans: A
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium
39. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
O
III
O
O
II
A) B) C) D) E)
IV
I=0.9 ppm, II=2.7 ppm, III=1.2 ppm, IV=0.9 ppm I=1.1 ppm, II=3.2 ppm, III=1.4 ppm, IV=0.9 ppm I=0.9 ppm, II=1.7 ppm, III=1.2 ppm, IV=1.1 ppm I=0.9 ppm, II=1.9 ppm, III=3.4 ppm, IV=0.9 ppm none of these Ans: B
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard 40. Predict the chemical shifts for the signals in the 1H NMR spectrum for the following compound. IV
II O O O
Ans:
I
III
O
4.4 ppm 1.9 ppm O O O
5.2 ppm
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard
5.7 ppm O
41. Predict the chemical shifts for the signals in the 1H NMR spectrum for the following compound? O
O
O
Ans:
O
4.2 ppm O
1.4 ppm
O
1.9 ppm
2.7 ppm
2.2 ppm
0.9 ppm
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 42. Aromatic protons produce signal in the range of 7-8 ppm, due to the _________effect of π electrons A) B) C) D) E)
diamagnetic anisotropy paramagnetic anisotropy diamagnetic isotropy paramagnetic isotropy none of these Ans: A
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 43. Which of the following protons appear most upfield in the 1H NMR spectrum? II
H
III H
H
IV I
A) B) C) D) E)
H
I II III IV none of these Ans: D
Topic: Integration Section: 16.6 Difficulty Level: Medium 44. A compound with molecular formula C8H14 has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal? I I
I III
8
A) B) C) D)
7
I-3H, II-9H, III-2H I-2H, II-9H, III-3H I-4H, II-6H, III-4H none of these Ans: A
Topic: Integration Section: 16.6 Difficulty Level: Medium
6
5
4 PPM
3
2
1
0
45. A compound with molecular formula C6H11N has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal? I II III
8
A) B) C) D)
7
I-6H, II-3H, III-2H I-5H, II-4H, III-2H I-6H, II-4H, III-1H none of these Ans: C
Topic: Integration Section: 16.6 Difficulty Level: Medium
6
5
4 PPM
3
2
1
0
46. A compound with molecular formula C8H10O has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal?
I III
II
IV
SDBS: National Institute of Advanced Industrial Science and Technology
Ans: I-3H, II-2H, III-3H, IV-2H
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 47. Which of the following four compounds gives a 1H NMR spectrum consisting of only a singlet? A) B) C) D) E)
1,1-dichloropropane 1,3-dichloropropane 1,2-dichloropropane 2,2-dichloropropane none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
48. How many 1H NMR signals will 2-chloro-3-methyl-2-butene exhibit? A) B) C) D) E)
1 2 3 4 none of these Ans: C
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 49. Which of the following compounds will display two triplets and a singlet in the 1 H NMR spectrum? A) B) C) D) E)
CH3CH(OCH3)2 CH3OCH2CH2OCH3 CH3OCH2CH(OH)CH3 CH3OCH2CH2CH2CH2OCH3 none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 50. Which of the following compounds will display a singlet, a triplet and a quartet in the 1 H NMR spectrum? A) 2-chloro-4-methylpentane B) 3-chloro-2-methylpentane C) 3-chloropentane D) 1-chloro-2,2-dimethylbutane E) 3-chloro-3-methylpentane Ans: E Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
51. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound.
O
Ans: doublet
quartet
septet
triplet O
Topic: Multiplicity Section: 16.7 Difficulty Level: Easy 52. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
N H
Ans:
sextet
singlet O
N H
triplet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
triplet
singlet
singlet
53. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
O
Ans:
multiplet
doublet O
singlet doublet
O
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 54. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
H O
doublet
Ans: O
sextet
singlet
H
singlet O
singlet
doublet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
55. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
HO
O
Ans:
NH2
singlet
triplet
O
singlet HO
singlet
O
NH2
triplet
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 56. Determine the multiplicity of each signal in the expected 1H NMR spectrum of 2,3dimethyl-2-pentanol. singlet
Ans:
quintet
OH
singlet
doublet
triplet sextet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 57. The coupling constant (J) for bromoethane is 7 Hz when the 1H NMR spectrum is acquired at 250 MHz. What is the coupling constant between these protons when the spectrum is acquired at 500 MHz? A) 3.5 Hz B) 7 Hz C) 14 Hz D) 21 Hz E) none of these Ans: B Topic: Multiplicity Section: 16.7 Difficulty Level: Hard
58. Which of the following is the maximum multiplicity observed for Hc protons in the following compound? Assume that Jcd and Jcb values are different. H c N
A) B) C) D) E)
d
a b 5 6 8 12 none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 59. Which of the following is the maximum multiplicity observed for Hb protons in the following compound? Assume that Jab and Jbc values are different. a
b A) B) C) D) E)
O
a c 9 12 21 24 none of these Ans: C
d
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 60. Presence of which of the following protons is confirmed by D2O exchange? A) B) C) D) E)
OH NH2 CH A&B none of these Ans: D
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium
61. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. I
III
O
O
II Ans: 0.9 ppm triplet
IV 3.9 ppm triplet O
O
sextet 1.7 ppm
singlet 2.4 ppm
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium 62. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. O
O
O
Ans:
septet 3.2 ppm O
doublet 1.1 ppm
O
sextet 1.4 ppm
O
triplet 2.7 ppm
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium
triplet 0.9 ppm
63. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. O O O
Ans:
O
doublet singlet 1.9 ppm 4.4 ppm
O O O
singlet 5.2 ppm
triplet O 5.7 ppm
Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 64. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O
O
H
H
A) B) C) D)
O
I
O
II
I=3 & II=2 signals I=4 & II=3 signals I=5 & II=3 signals none of these Ans: B
Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium
65. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O O
O
O
II
I
Ans: Both compounds will have three signals. Compound I: a triplet, a quartet and a singlet Compound II: a singlet, a triplet and a quintet Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 66. How would you use 1H NMR spectroscopy to distinguish between the following two compounds?
O
O
O
I
II
O
Ans: Both compounds will have five signals. Compound I: a doublet, a septet, two triplets and a sextet. Compound II: a doublet, a multiplet, a quartet and a triplet. Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 67. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O O O
II
I
O
Ans: Both compounds will have five signals. The Ha proton in compound I will appear more downfield than the Ha proton in compound II. O
O O
I
a
II
O
a
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 68. A compound with a molecular formula C9H12 has the following 1H NMR spectrum. Which of the following structures is consistent with this spectrum? 9
3
7
I
A) B) C) D) E)
6
5
4 PPM
II
I II III IV none of these Ans: C
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
3
2
III
1
0
IV
69. Which of the following structures is consistent with this 1H NMR spectrum? 3
5 1
1
SDBS: National Institute of Advanced Industrial Science and Technology
O
A) B) C) D) E)
O
O
I
II
I II III IV none of these Ans: B
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
III
IV
70. A compound with a molecular formula C9H10O2 has the following 1H NMR spectrum. Which of the following structures is consistent with this spectrum?
12
10
8
PPM
6
4
2 O
H
OH
O
I
A) B) C) D) E)
I II III IV none of these Ans: B
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
O
O
II
III
IV
0
71. A compound with a molecular formula C5H10O has the following 1H NMR spectrum. Propose a structure for this compound. 9
1 10
8
6
PPM
4
2
0
Ans: H
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 72. Propose a structure for a compound with molecular formula C5H11Cl, that fits the following spectroscopic data: 1 H NMR: 0.9δ (triplet, I=3), 1.3δ (sextet, I=2), 1.5δ (quartet, I=2), 1.6δ (doublet, I=3), 3.6δ (sextet, I=1) Ans:
Cl
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
73. Propose a structure for a compound with molecular formula C8H14O3 that fits the following spectroscopic data. IR:1820cm-1, 1760cm-1 1 H NMR: 1.0δ (triplet, I=6), 1.6δ (sextet, I=4), 2.2δ (triplet, I=4) O
Ans:
O
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 74. Propose a structure for a compound with molecular formula C10H12O that fits the following spectroscopic data. IR:1680cm-1 1 H NMR: 1.0δ (triplet, I=3), 1.5δ (sextet, I=2), 2.6δ (triplet, I=4), 7.4δ (triplet, I=2), 7.5δ (triplet, I=1), 7.9δ (doublet, I=2) Ans:
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
75. A compound with a molecular formula C8H16O has the following 1H NMR spectrum. Provide a structure that is consistent with this spectrum? 6
3 2
2
2
1
2
Ans:
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
PPM
1
0
76. A compound with a molecular formula C10H12O2 has the following HNMR spectrum. Which of the following structures is consistent with this spectrum?
3 2
2
2
2
1
11
10
9
8
7
6 PPM
5
4
O O CH
O
O
II
I
A) B) C) D) E)
I II III IV none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy
III
O
O
COH
COH
IV
3
2
1
0
77. How many signals would you expect to find in the 13C NMR spectrum of the following compound? O
A) B) C) D) E)
6 7 8 9 none of these Ans: B
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy 78. How many signals would you expect to find in the 13C NMR spectrum of the following compound? O
A) B) C) D) E)
O
2 3 4 5 none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium
79. How many signals would you expect to find in the 13C NMR spectrum of the following compound?
A) B) C) D) E)
6 7 8 9 none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 80. How many signals would you expect to find in the 13C NMR spectrum of the following compounds? Cl
O
O
I
A) B) C) D) E)
I-5, II-8 I-3, II-6 I-4, II-8 I-5, II-6 none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy
II
CH2CH3
81. Which of the following carbon atoms will display the signal most downfield in the 13C NMR spectrum? O C
N
I
A) B) C) D) E)
I II III IV none of these Ans: B
F
C
C
C
II
III
IV
C
C
V
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 82. Which of the following compounds will display four signals in the 13C NMR spectrum? A) B) C) D) E)
2,6-dimethylheptane 2,4-dimethylheptane 3,5-dimethylheptane 4,4-dimethylheptane none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium
83. Which of the following compounds will display five signals in the 13C NMR spectrum? Br
Br
I
A) B) C) D) E)
Br
Br
Br
Br
Br
II
III
IV Br
I II III IV none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 84. Which of the following 13C NMR chemical shifts corresponds to Ca in the following compound? a
O
A) B) C) D) E)
120 ppm 145 ppm 159 ppm 200 ppm none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
85. Which of the following compounds is consistent with the following 13C NMR spectrum?
200
180
160
140
120
80
60
O
O O
I
A) B) C) D) E)
100 PPM
II
I II III IV none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
O
III
IV
40
20
0
86. Which of the following compounds is consistent with the following 13C NMR spectrum?
80
70
60
50
40 PPM
30
20
10
OH
OH HO
I
A) B) C) D) E)
I II III IV none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
II
III
IV OH
0
87. Which of the following compounds is consistent with the following 13C NMR spectrum?
60
50
40
30 PPM
20
Cl
Cl
Cl
I
A) B) C) D)
I II III none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
II
III
10
0
88. Which of the following compounds is consistent with the following 13C NMR spectrum?
80
70
60
50
40 PPM
30
20
10
0
OH
OH HO
I
A) B) C) D) E)
I II III IV none of these Ans: C
II
III
IV OH
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy 89. Which of the following display a signal in the DEPT-90 13C NMR spectroscopy? A) B) C) D) E)
CH3 CH2 CH C none of these Ans: C
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy
90. Which of the following displays a negative signal in the DEPT-135 13C NMR spectroscopy? A) CH3 B) CH2 C) CH D) C E) none of these Ans: B Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy 91. Which of the following does not display a signal in the DEPT-135 13C NMR spectroscopy? A) CH3 B) CH2 C) CH D) C E) none of these Ans: D Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Medium 92. Which of the following compounds will not display a carbonyl carbon signal in the DEPT-90 and DEPT-135 13C NMR spectroscopy?
A) B) C) D) E)
I
O
O
O
H
II
O
I II III II & III none of these Ans: D
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Medium
III
N H
DEPT-90 DEPT-90 DEPT-135 DEPT-135
93. A compound with molecular formula C5H10Br2 displays the following 13C NMR along with the DEPT-90 and DEPT-135 13CNMR spectrum. What is the structure for this Broadband decoupled compound?
Broadband decoupled
Ans: BrCH2CH2CH2CH2CH2Br Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Hard 94. A compound with molecular formula C7H7Br displays the following 13C NMR along with the DEPT-90 and DEPT-135 13CNMR spectrum. What is the structure for this compound?
Ans: Br
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Medium
95. A compound with molecular formula C11H14O displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
220
200
180
160
140
120 100 PPM
80
60
40
20
Three spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology
Ans:
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
0
6
Difficulty Level: Medium 3
96. A compound with molecular formula C7H14O2 displays the following IR, 1HNMR and 13 1 Propose a structure 2 for2 this compound. CNMR spectrum.
180
160
140
120
100 PPM
80
60
40
Three spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology
Ans:
O
O
Topic: Integrated Spectroscopy
20
0
Section: 15.6, 16.10, 16.12 Difficulty Level: Hard
97. A compound with molecular formula C5H7NO2 displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
SDBS: National Institute of Advanced Industrial Science and Technology
SDBS: National Institute of Advanced Industrial Science and Technology
SDBS: National Institute of Advanced Industrial Science and Technology O Ans: N
C O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
Difficulty Level: Medium 98. Propose a structure for a compound with molecular formula C5H10O that fits the following spectroscopic data. IR:1720cm-1 1 H NMR: 1.1δ (doublet, I=6), 2.1δ (singet, I=3), 2.7δ (septet, I=1) 13 C NMR: 15, 22, 45, 210 Ans:
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Medium 99. Propose a structure for a compound with molecular formula C8H19N that fits the following spectroscopic data. IR: 3400cm-1 1 H NMR: 0.9δ (triplet, I=6), 1.1δ (singlet, I=1, exchanges with D2O), 1.3δ (sextet, I=4), 1.4δ (quintet, I=4), 2.6δ (triplet, I=4) 13 C NMR: 13.7, 20.5, 30.4, 49.2 Ans:
N H
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Hard 100. Propose a structure for a compound with molecular formula C5H12O2 that fits the following spectroscopic data. IR: 1200cm-1 1 H NMR: 1.4δ (singlet, I=6), 3.2δ (singlet, I=6) 13 C NMR: 28, 45, 100 Ans: O
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
Difficulty Level: Hard 101. Propose a structure for a compound with molecular formula C6H10O that fits the following spectroscopic data. IR: 3400 cm-1(broad), 3250 cm-1(sharp), 2150 cm-1 1 H NMR: 1.0δ (triplet, I=3), 1.5δ (singlet, I=3), 1.6δ (quartet, I=2), 2.5δ (singlet, I=1), 3.4δ (singlet, I=1) 13 C NMR: 5, 26, 35, 67, 69 Ans:
OH
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Hard 102. Propose a structure for a compound with molecular formula C8H15ClO3 that fits the following spectroscopic data. IR: 1780 cm-1, 1150 cm-1 1 H NMR: 1.1δ (triplet, I=6), 1.9δ (quartet, I=2), 2.8δ (triplet, I=2), 3.4δ (quartet, I=4), 4.2δ (triplet, I=1) 13 C NMR: 15, 31, 38, 57, 100, 173 O
Ans: O
Cl O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 & 16.13
DEPT-90
DEPT-135
Difficulty Level: Medium 103. A compound with molecular formula C3H6O2 displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
Broadband decoupled
Ans:
O
OH
Topic: Integrated Spectroscopy
DEPT-90
DEPT-135
Broadband decoupled
Section: 15.6, 16.10, 16.12 & 16.13 Difficulty Level: Medium 104. A compound with molecular formula C6H12O displays the following IR, 1HNMR and 13 CNMR spectrum. 1Propose a structure for this compound.
Ans: O
Topic: Integrated Spectroscopy
DEPT-90
DEPT-135
Broadband decoupled
Section: 15.6, 16.10, 16.12 & 16.13 Difficulty Level: Hard 105. A compound with molecular formula C6H4Cl2O displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
Ans:
Cl
OH
Cl
nucleus with odd number of protons & odd number of neutrons nucleus with odd number of protons &even number of neutrons nucleus with even number of protons & odd number of neutrons nucleus with even number of protons & even number of neutrons none of these Ans: D
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Easy 2. How many nuclear spin states are possible for the 1H nucleus? A) B) C) D) E)
1 2 4 5 none of these Ans: B
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Easy 3. Which of the following electromagnetic radiation is used in NMR spectroscopy? A) B) C) D) E)
UV IR visible γ-rays radio wave Ans: E
Topic: Introduction to NMR Section: 16.1 Difficulty Level: Medium
4. _______ protons experience a net magnetic field strength that is smaller than the applied magnetic field. A) deshielded B) shielded C) paramagnetic D) diamagnetic E) none of these Ans: B Topic: Introduction to NMR Section: 16.1 Difficulty Level: Medium 5. _______ protons experience a net magnetic field strength that is higher than the applied magnetic field. A) deshielded B) shielded C) paramagnetic D) diamagnetic E) none of these Ans: A Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Medium 6. Which of the following is true about the relationship between the energy gap (ΔE) between the spin states for a 1H nucleus and the strength of the external magnetic field?. A) they are inversely proportional B) they are directly proportional C) there is no relationship D) the magnetic field is slightly less E) none of these Ans: B Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Medium
7. The strength of the magnetic field is a determining factor for the range of _______that must be used for NMR spectrometer. A) temperature B) frequencies C) tesla D) spin states D) none of these Ans: B Topic: Acquiring a 1HNMR spectrum Section: 16.2 Difficulty Level: Easy 8. Which of the following is not a common solvent used for acquiring a 1H NMR spectrum? A) CDCl3 B) CCl4 C) CD3CN D) CH3OH E) D2O Ans: D Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 9. Which of the following is true about the number of signals in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different kinds of protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: C
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy
10. Which of the following is true about the location of signals in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: D
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 11. Which of the following is true about the area under each signal in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: E
Topic: Characteristics of a 1HNMR spectrum Section: 16.3 Difficulty Level: Easy 12. Which of the following is true about the shape of the signal in a 1H NMR spectrum? A) B) C) D) E)
it indicates the number of neighboring protons it indicates the electronic environment of neighboring protons it indicates the number of different protons it indicates the electronic environment of absorbing protons it indicates the number of protons in the signal Ans: A
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
13. Which of the following type of protons are chemically non equivalent? A) B) C) D) E)
homotopic enantiotopic diastereotopic A&B B&C Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 14. Which of the following type of protons are chemically equivalent? A) B) C) D) E)
homotopic enantiotopic diastereotopic A&B B&C Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Easy 15. Protons Ha and Hb in the following compound are _________. Ha
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: A
Topic: Number of signals Section: 16.4 Difficulty Level: Easy
Hb
16. Protons Ha and Hb in the following compound are _________. Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: B
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 17. Protons Ha and Hb in the following compound are _________. Ha
Hb
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
18. Protons Ha and Hb in the following compound are _________. Br
H
Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 19. Protons Ha and Hb in the following compound are _________. OH
Ha
A) B) C) D) E)
Hb
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
20. Protons Ha and Hb in the following compound are _________. Ha Hb
A) B) C) D) E)
homotopic enantiotopic diastereotopic mesotopic none of these Ans: C
Topic: Number of signals Section: 16.4 Difficulty Level: Easy 21. How many signals would you expect to find in the 1H NMR spectrum of CH3OCH2CH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: C Topic: Number of signals Section: 16.4 Difficulty Level: Easy 22. How many signals would you expect to find in the 1H NMR spectrum of CH3OCH2CH2OCH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: B Topic: Number of signals Section: 16.4 Difficulty Level: Easy
23. How many signals would you expect to find in the 1H NMR spectrum of (CH3)2CHCH2CH2CH3? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: E Topic: Number of signals Section: 16.4 Difficulty Level: Medium 24. How many signals would you expect to find in the 1H NMR spectrum of HOCH2CH2CH2CH2OH? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: C Topic: Number of signals Section: 16.4 Difficulty Level: Medium 25. How many signals would you expect to find in the 1H NMR spectrum of the following compound?
A) B) C) D) E)
4 5 6 7 8 Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Medium
26. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
A) B) C) D) E)
4 5 6 7 8 Ans: B
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 27. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
A) B) C) D) E)
OH
4 5 6 7 9 Ans: D
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 28. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
Ans: 4
Topic: Number of signals Section: 16.4 Difficulty Level: Medium 29. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O Cl
Ans: 6 Topic: Number of signals Section: 16.4 Difficulty Level: Medium 30. How many signals would you expect to find in the 1H NMR spectrum of the following compound? O
O
Ans: 3 Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 31. The 1H NMR spectrum of bromoethane shows a signal at 3.5ppm when the spectrum is recorded using a 60-MHz spectrometer. Where do you expect to see the signal if a 300MHz instrument is used instead? A) 3.5 ppm B) 7.5 ppm C) 6.8 ppm D) 5.8 ppm E) none of these Ans: A Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 32. ______is used as a reference for recording NMR spectroscopy and is assigned a chemical shift value of zero. Ans: Tetramethylsilane (TMS)/ (CH3)4Si
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 33. Which of the indicated protons in the following compound would appear most downfield in the 1H NMR spectrum? III
OH
I II
A) B) C) D)
IV
I II III IV Ans: D
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 34. Which of the indicated protons in the following compound would appear most downfield in the 1H NMR spectrum? II
III
H
H
H
C
C
C
I
H
H
IV CH3
F
V
A) B) C) D) E)
I II III IV V Ans: E
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard
H
35. Which of the indicated protons in the following compound would appear most upfield in the 1H NMR spectrum? II
O
IV
O
O
A) B) C) D) E)
I II III IV I & III Ans: A
F
I
III
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy 36. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
O
HO
II
A) B) C) D) E)
III
I=3.7 ppm, II=2.7 ppm, III=1.9 ppm I=3.7 ppm, II=2.2 ppm, III=1.9 ppm I=3.9 ppm, II=2.7 ppm, III=1.9 ppm I=3.9 ppm, II=2.2 ppm, III=2.4 ppm none of these Ans: C
Topic: Chemical shift Section: 16.5 Difficulty Level: Easy
37. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? II
O O
I
A) B) C) D) E)
III
IV
I=3.9 ppm, II=4.2 ppm, III=2.2 ppm, IV=3.4 ppm I=3.4 ppm, II=2.2 ppm, III=2.2 ppm, IV=3.4 ppm I=3.4 ppm, II=2.2 ppm, III=4.2 ppm, IV=3.4 ppm I=3.4 ppm, II=4.2 ppm, III=4.2 ppm, IV=3.4 ppm none of these Ans: D
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 38. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
III
O
O
A) B) C) D) E)
II
IV
I=0.9 ppm, II=1.7 ppm, III=3.9 ppm, IV=2.4 ppm I=0.9 ppm, II=1.2 ppm, III=3.7 ppm, IV=1.9 ppm I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=2.4 ppm I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=1.9 ppm none of these Ans: A
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium
39. Which of the following is a correct prediction of the chemical shifts for the signals in the 1H NMR spectrum for the following compound? I
O
III
O
O
II
A) B) C) D) E)
IV
I=0.9 ppm, II=2.7 ppm, III=1.2 ppm, IV=0.9 ppm I=1.1 ppm, II=3.2 ppm, III=1.4 ppm, IV=0.9 ppm I=0.9 ppm, II=1.7 ppm, III=1.2 ppm, IV=1.1 ppm I=0.9 ppm, II=1.9 ppm, III=3.4 ppm, IV=0.9 ppm none of these Ans: B
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard 40. Predict the chemical shifts for the signals in the 1H NMR spectrum for the following compound. IV
II O O O
Ans:
I
III
O
4.4 ppm 1.9 ppm O O O
5.2 ppm
Topic: Chemical shift Section: 16.5 Difficulty Level: Hard
5.7 ppm O
41. Predict the chemical shifts for the signals in the 1H NMR spectrum for the following compound? O
O
O
Ans:
O
4.2 ppm O
1.4 ppm
O
1.9 ppm
2.7 ppm
2.2 ppm
0.9 ppm
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 42. Aromatic protons produce signal in the range of 7-8 ppm, due to the _________effect of π electrons A) B) C) D) E)
diamagnetic anisotropy paramagnetic anisotropy diamagnetic isotropy paramagnetic isotropy none of these Ans: A
Topic: Chemical shift Section: 16.5 Difficulty Level: Medium 43. Which of the following protons appear most upfield in the 1H NMR spectrum? II
H
III H
H
IV I
A) B) C) D) E)
H
I II III IV none of these Ans: D
Topic: Integration Section: 16.6 Difficulty Level: Medium 44. A compound with molecular formula C8H14 has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal? I I
I III
8
A) B) C) D)
7
I-3H, II-9H, III-2H I-2H, II-9H, III-3H I-4H, II-6H, III-4H none of these Ans: A
Topic: Integration Section: 16.6 Difficulty Level: Medium
6
5
4 PPM
3
2
1
0
45. A compound with molecular formula C6H11N has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal? I II III
8
A) B) C) D)
7
I-6H, II-3H, III-2H I-5H, II-4H, III-2H I-6H, II-4H, III-1H none of these Ans: C
Topic: Integration Section: 16.6 Difficulty Level: Medium
6
5
4 PPM
3
2
1
0
46. A compound with molecular formula C8H10O has the following 1H NMR spectrum. Which of the following is the correct number of protons giving rise to each signal?
I III
II
IV
SDBS: National Institute of Advanced Industrial Science and Technology
Ans: I-3H, II-2H, III-3H, IV-2H
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 47. Which of the following four compounds gives a 1H NMR spectrum consisting of only a singlet? A) B) C) D) E)
1,1-dichloropropane 1,3-dichloropropane 1,2-dichloropropane 2,2-dichloropropane none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
48. How many 1H NMR signals will 2-chloro-3-methyl-2-butene exhibit? A) B) C) D) E)
1 2 3 4 none of these Ans: C
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 49. Which of the following compounds will display two triplets and a singlet in the 1 H NMR spectrum? A) B) C) D) E)
CH3CH(OCH3)2 CH3OCH2CH2OCH3 CH3OCH2CH(OH)CH3 CH3OCH2CH2CH2CH2OCH3 none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 50. Which of the following compounds will display a singlet, a triplet and a quartet in the 1 H NMR spectrum? A) 2-chloro-4-methylpentane B) 3-chloro-2-methylpentane C) 3-chloropentane D) 1-chloro-2,2-dimethylbutane E) 3-chloro-3-methylpentane Ans: E Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
51. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound.
O
Ans: doublet
quartet
septet
triplet O
Topic: Multiplicity Section: 16.7 Difficulty Level: Easy 52. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
N H
Ans:
sextet
singlet O
N H
triplet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
triplet
singlet
singlet
53. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
O
Ans:
multiplet
doublet O
singlet doublet
O
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 54. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
H O
doublet
Ans: O
sextet
singlet
H
singlet O
singlet
doublet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium
55. Determine the multiplicity of each signal in the expected 1H NMR spectrum of the following compound. O
HO
O
Ans:
NH2
singlet
triplet
O
singlet HO
singlet
O
NH2
triplet
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 56. Determine the multiplicity of each signal in the expected 1H NMR spectrum of 2,3dimethyl-2-pentanol. singlet
Ans:
quintet
OH
singlet
doublet
triplet sextet
Topic: Multiplicity Section: 16.7 Difficulty Level: Medium 57. The coupling constant (J) for bromoethane is 7 Hz when the 1H NMR spectrum is acquired at 250 MHz. What is the coupling constant between these protons when the spectrum is acquired at 500 MHz? A) 3.5 Hz B) 7 Hz C) 14 Hz D) 21 Hz E) none of these Ans: B Topic: Multiplicity Section: 16.7 Difficulty Level: Hard
58. Which of the following is the maximum multiplicity observed for Hc protons in the following compound? Assume that Jcd and Jcb values are different. H c N
A) B) C) D) E)
d
a b 5 6 8 12 none of these Ans: D
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 59. Which of the following is the maximum multiplicity observed for Hb protons in the following compound? Assume that Jab and Jbc values are different. a
b A) B) C) D) E)
O
a c 9 12 21 24 none of these Ans: C
d
Topic: Multiplicity Section: 16.7 Difficulty Level: Hard 60. Presence of which of the following protons is confirmed by D2O exchange? A) B) C) D) E)
OH NH2 CH A&B none of these Ans: D
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium
61. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. I
III
O
O
II Ans: 0.9 ppm triplet
IV 3.9 ppm triplet O
O
sextet 1.7 ppm
singlet 2.4 ppm
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium 62. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. O
O
O
Ans:
septet 3.2 ppm O
doublet 1.1 ppm
O
sextet 1.4 ppm
O
triplet 2.7 ppm
Topic: 1H NMR spectrum Section: 16.8 Difficulty Level: Medium
triplet 0.9 ppm
63. Determine the multiplicity and predict the chemical shifts of each signal in the expected 1 H NMR spectrum of the following compound. O O O
Ans:
O
doublet singlet 1.9 ppm 4.4 ppm
O O O
singlet 5.2 ppm
triplet O 5.7 ppm
Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 64. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O
O
H
H
A) B) C) D)
O
I
O
II
I=3 & II=2 signals I=4 & II=3 signals I=5 & II=3 signals none of these Ans: B
Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium
65. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O O
O
O
II
I
Ans: Both compounds will have three signals. Compound I: a triplet, a quartet and a singlet Compound II: a singlet, a triplet and a quintet Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 66. How would you use 1H NMR spectroscopy to distinguish between the following two compounds?
O
O
O
I
II
O
Ans: Both compounds will have five signals. Compound I: a doublet, a septet, two triplets and a sextet. Compound II: a doublet, a multiplet, a quartet and a triplet. Topic: 1H NMR spectroscopy to distinguish between compounds Section: 16.9 Difficulty Level: Medium 67. How would you use 1H NMR spectroscopy to distinguish between the following two compounds? O O O
II
I
O
Ans: Both compounds will have five signals. The Ha proton in compound I will appear more downfield than the Ha proton in compound II. O
O O
I
a
II
O
a
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 68. A compound with a molecular formula C9H12 has the following 1H NMR spectrum. Which of the following structures is consistent with this spectrum? 9
3
7
I
A) B) C) D) E)
6
5
4 PPM
II
I II III IV none of these Ans: C
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
3
2
III
1
0
IV
69. Which of the following structures is consistent with this 1H NMR spectrum? 3
5 1
1
SDBS: National Institute of Advanced Industrial Science and Technology
O
A) B) C) D) E)
O
O
I
II
I II III IV none of these Ans: B
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
III
IV
70. A compound with a molecular formula C9H10O2 has the following 1H NMR spectrum. Which of the following structures is consistent with this spectrum?
12
10
8
PPM
6
4
2 O
H
OH
O
I
A) B) C) D) E)
I II III IV none of these Ans: B
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
O
O
II
III
IV
0
71. A compound with a molecular formula C5H10O has the following 1H NMR spectrum. Propose a structure for this compound. 9
1 10
8
6
PPM
4
2
0
Ans: H
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 72. Propose a structure for a compound with molecular formula C5H11Cl, that fits the following spectroscopic data: 1 H NMR: 0.9δ (triplet, I=3), 1.3δ (sextet, I=2), 1.5δ (quartet, I=2), 1.6δ (doublet, I=3), 3.6δ (sextet, I=1) Ans:
Cl
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
73. Propose a structure for a compound with molecular formula C8H14O3 that fits the following spectroscopic data. IR:1820cm-1, 1760cm-1 1 H NMR: 1.0δ (triplet, I=6), 1.6δ (sextet, I=4), 2.2δ (triplet, I=4) O
Ans:
O
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium 74. Propose a structure for a compound with molecular formula C10H12O that fits the following spectroscopic data. IR:1680cm-1 1 H NMR: 1.0δ (triplet, I=3), 1.5δ (sextet, I=2), 2.6δ (triplet, I=4), 7.4δ (triplet, I=2), 7.5δ (triplet, I=1), 7.9δ (doublet, I=2) Ans:
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
75. A compound with a molecular formula C8H16O has the following 1H NMR spectrum. Provide a structure that is consistent with this spectrum? 6
3 2
2
2
1
2
Ans:
O
Topic: Analyzing a 1H NMR spectrum Section: 16.10 Difficulty Level: Medium
PPM
1
0
76. A compound with a molecular formula C10H12O2 has the following HNMR spectrum. Which of the following structures is consistent with this spectrum?
3 2
2
2
2
1
11
10
9
8
7
6 PPM
5
4
O O CH
O
O
II
I
A) B) C) D) E)
I II III IV none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy
III
O
O
COH
COH
IV
3
2
1
0
77. How many signals would you expect to find in the 13C NMR spectrum of the following compound? O
A) B) C) D) E)
6 7 8 9 none of these Ans: B
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy 78. How many signals would you expect to find in the 13C NMR spectrum of the following compound? O
A) B) C) D) E)
O
2 3 4 5 none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium
79. How many signals would you expect to find in the 13C NMR spectrum of the following compound?
A) B) C) D) E)
6 7 8 9 none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 80. How many signals would you expect to find in the 13C NMR spectrum of the following compounds? Cl
O
O
I
A) B) C) D) E)
I-5, II-8 I-3, II-6 I-4, II-8 I-5, II-6 none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Easy
II
CH2CH3
81. Which of the following carbon atoms will display the signal most downfield in the 13C NMR spectrum? O C
N
I
A) B) C) D) E)
I II III IV none of these Ans: B
F
C
C
C
II
III
IV
C
C
V
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 82. Which of the following compounds will display four signals in the 13C NMR spectrum? A) B) C) D) E)
2,6-dimethylheptane 2,4-dimethylheptane 3,5-dimethylheptane 4,4-dimethylheptane none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium
83. Which of the following compounds will display five signals in the 13C NMR spectrum? Br
Br
I
A) B) C) D) E)
Br
Br
Br
Br
Br
II
III
IV Br
I II III IV none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Medium 84. Which of the following 13C NMR chemical shifts corresponds to Ca in the following compound? a
O
A) B) C) D) E)
120 ppm 145 ppm 159 ppm 200 ppm none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
85. Which of the following compounds is consistent with the following 13C NMR spectrum?
200
180
160
140
120
80
60
O
O O
I
A) B) C) D) E)
100 PPM
II
I II III IV none of these Ans: A
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
O
III
IV
40
20
0
86. Which of the following compounds is consistent with the following 13C NMR spectrum?
80
70
60
50
40 PPM
30
20
10
OH
OH HO
I
A) B) C) D) E)
I II III IV none of these Ans: D
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
II
III
IV OH
0
87. Which of the following compounds is consistent with the following 13C NMR spectrum?
60
50
40
30 PPM
20
Cl
Cl
Cl
I
A) B) C) D)
I II III none of these Ans: C
Topic: 13C NMR spectroscopy Section: 16.11 & 16.12 Difficulty Level: Hard
II
III
10
0
88. Which of the following compounds is consistent with the following 13C NMR spectrum?
80
70
60
50
40 PPM
30
20
10
0
OH
OH HO
I
A) B) C) D) E)
I II III IV none of these Ans: C
II
III
IV OH
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy 89. Which of the following display a signal in the DEPT-90 13C NMR spectroscopy? A) B) C) D) E)
CH3 CH2 CH C none of these Ans: C
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy
90. Which of the following displays a negative signal in the DEPT-135 13C NMR spectroscopy? A) CH3 B) CH2 C) CH D) C E) none of these Ans: B Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Easy 91. Which of the following does not display a signal in the DEPT-135 13C NMR spectroscopy? A) CH3 B) CH2 C) CH D) C E) none of these Ans: D Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Medium 92. Which of the following compounds will not display a carbonyl carbon signal in the DEPT-90 and DEPT-135 13C NMR spectroscopy?
A) B) C) D) E)
I
O
O
O
H
II
O
I II III II & III none of these Ans: D
Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Medium
III
N H
DEPT-90 DEPT-90 DEPT-135 DEPT-135
93. A compound with molecular formula C5H10Br2 displays the following 13C NMR along with the DEPT-90 and DEPT-135 13CNMR spectrum. What is the structure for this Broadband decoupled compound?
Broadband decoupled
Ans: BrCH2CH2CH2CH2CH2Br Topic: DEPT 13C NMR spectroscopy Section: 16.13 Difficulty Level: Hard 94. A compound with molecular formula C7H7Br displays the following 13C NMR along with the DEPT-90 and DEPT-135 13CNMR spectrum. What is the structure for this compound?
Ans: Br
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Medium
95. A compound with molecular formula C11H14O displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
220
200
180
160
140
120 100 PPM
80
60
40
20
Three spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology
Ans:
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
0
6
Difficulty Level: Medium 3
96. A compound with molecular formula C7H14O2 displays the following IR, 1HNMR and 13 1 Propose a structure 2 for2 this compound. CNMR spectrum.
180
160
140
120
100 PPM
80
60
40
Three spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology
Ans:
O
O
Topic: Integrated Spectroscopy
20
0
Section: 15.6, 16.10, 16.12 Difficulty Level: Hard
97. A compound with molecular formula C5H7NO2 displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
SDBS: National Institute of Advanced Industrial Science and Technology
SDBS: National Institute of Advanced Industrial Science and Technology
SDBS: National Institute of Advanced Industrial Science and Technology O Ans: N
C O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
Difficulty Level: Medium 98. Propose a structure for a compound with molecular formula C5H10O that fits the following spectroscopic data. IR:1720cm-1 1 H NMR: 1.1δ (doublet, I=6), 2.1δ (singet, I=3), 2.7δ (septet, I=1) 13 C NMR: 15, 22, 45, 210 Ans:
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Medium 99. Propose a structure for a compound with molecular formula C8H19N that fits the following spectroscopic data. IR: 3400cm-1 1 H NMR: 0.9δ (triplet, I=6), 1.1δ (singlet, I=1, exchanges with D2O), 1.3δ (sextet, I=4), 1.4δ (quintet, I=4), 2.6δ (triplet, I=4) 13 C NMR: 13.7, 20.5, 30.4, 49.2 Ans:
N H
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Hard 100. Propose a structure for a compound with molecular formula C5H12O2 that fits the following spectroscopic data. IR: 1200cm-1 1 H NMR: 1.4δ (singlet, I=6), 3.2δ (singlet, I=6) 13 C NMR: 28, 45, 100 Ans: O
O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12
Difficulty Level: Hard 101. Propose a structure for a compound with molecular formula C6H10O that fits the following spectroscopic data. IR: 3400 cm-1(broad), 3250 cm-1(sharp), 2150 cm-1 1 H NMR: 1.0δ (triplet, I=3), 1.5δ (singlet, I=3), 1.6δ (quartet, I=2), 2.5δ (singlet, I=1), 3.4δ (singlet, I=1) 13 C NMR: 5, 26, 35, 67, 69 Ans:
OH
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 Difficulty Level: Hard 102. Propose a structure for a compound with molecular formula C8H15ClO3 that fits the following spectroscopic data. IR: 1780 cm-1, 1150 cm-1 1 H NMR: 1.1δ (triplet, I=6), 1.9δ (quartet, I=2), 2.8δ (triplet, I=2), 3.4δ (quartet, I=4), 4.2δ (triplet, I=1) 13 C NMR: 15, 31, 38, 57, 100, 173 O
Ans: O
Cl O
Topic: Integrated Spectroscopy Section: 15.6, 16.10, 16.12 & 16.13
DEPT-90
DEPT-135
Difficulty Level: Medium 103. A compound with molecular formula C3H6O2 displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
Broadband decoupled
Ans:
O
OH
Topic: Integrated Spectroscopy
DEPT-90
DEPT-135
Broadband decoupled
Section: 15.6, 16.10, 16.12 & 16.13 Difficulty Level: Medium 104. A compound with molecular formula C6H12O displays the following IR, 1HNMR and 13 CNMR spectrum. 1Propose a structure for this compound.
Ans: O
Topic: Integrated Spectroscopy
DEPT-90
DEPT-135
Broadband decoupled
Section: 15.6, 16.10, 16.12 & 16.13 Difficulty Level: Hard 105. A compound with molecular formula C6H4Cl2O displays the following IR, 1HNMR and 13 CNMR spectrum. Propose a structure for this compound.
Ans:
Cl
OH
Cl
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