Deck 16: Nuclear Magnetic Resonance Spectroscopy

Question 1

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Answer 1

diastereotopic

Question 2

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Answer 2

diastereotopic

Question 3

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Answer 3

diastereotopic

Question 4

Which of the following is true about the number of signals in a ¹H NMR spectrum?

A)it indicates the number of neighboring protons
B)it indicates the electronic environment of neighboring protons
C)it indicates the number of different kinds of protons
D)it indicates the electronic environment of absorbing protons
E)it indicates the number of protons in the signal

Question 5

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Question 6

Which of the following is true about the location of signals in a ¹H NMR spectrum?

A)it indicates the number of neighboring protons
B)it indicates the electronic environment of neighboring protons
C)it indicates the number of different protons
D)it indicates the electronic environment of absorbing protons
E)it indicates the number of protons in the signal

Question 7

_______ 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

Question 8

Which of the following is true about the shape of the signal in a ¹H NMR spectrum?

A)it indicates the number of neighboring protons
B)it indicates the electronic environment of neighboring protons
C)it indicates the number of different protons
D)it indicates the electronic environment of absorbing protons
E)it indicates the number of protons in the signal

Question 9

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Question 10

Which of the following is true about the area under each signal in a ¹H NMR spectrum?

A)it indicates the number of neighboring protons
B)it indicates the electronic environment of neighboring protons
C)it indicates the number of different protons
D)it indicates the electronic environment of absorbing protons
E)it indicates the number of protons in the signal

Question 11

Which of the following type of protons are chemically non equivalent?

A)homotopic
B)enantiotopic
C)diastereotopic
D)A & B
E)B & C

Question 12

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

Question 13

_______ 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

Question 14

How many nuclear spin states are possible for the ¹H nucleus?

A)1
B)2
C)4
D)5
E)none of these

Question 15

Which of the following can not be probed by an NMR spectrometer?

A)nucleus with odd number of protons & odd number of neutrons
B)nucleus with odd number of protons &even number of neutrons
C)nucleus with even number of protons & odd number of neutrons
D)nucleus with even number of protons & even number of neutrons
E)none of these

Question 16

Protons H_a and H_b in the following compound are _________.

A)homotopic
B)enantiotopic
C)diastereotopic
D)mesotopic
E)none of these

Question 17

Which of the following electromagnetic radiation is used in NMR spectroscopy?

A)UV
B)IR
C)visible
D) $\gamma$ -rays
E)radio wave

Question 18

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)none of these
E)spin states

Question 19

Which of the following is true about the relationship between the energy gap ( $\Delta$ E)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

Question 20

Which of the following type of protons are chemically equivalent?

A)homotopic
B)enantiotopic
C)diastereotopic
D)A & B
E)B & C

Question 21

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

Question 22

Which of the following four compounds gives a ¹H NMR spectrum consisting of only a singlet?

A)1,1-dichloropropane
B)1,3-dichloropropane
C)1,2-dichloropropane
D)2,2-dichloropropane
E)none of these

Question 23

How many ¹H NMR signals will 2-chloro-3-methyl-2-butene exhibit?

A)1
B)2
C)3
D)4
E)none of these

Question 24

Which of the following is a correct prediction of the chemical shifts for the signals in the ¹H NMR spectrum for the following compound?

A)I=3.7 ppm,II=2.7 ppm,III=1.9 ppm
B)I=3.7 ppm,II=2.2 ppm,III=1.9 ppm
C)I=3.9 ppm,II=2.7 ppm,III=1.9 ppm
D)I=3.9 ppm,II=2.2 ppm,III=2.4 ppm
E)none of these

Question 25

Aromatic protons produce signal in the range of 7-8 ppm,due to the _________effect of $\pi$ electrons

A)diamagnetic anisotropy
B)paramagnetic anisotropy
C)diamagnetic isotropy
D)paramagnetic isotropy
E)none of these

Question 26

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

Question 27

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

Question 28

Which of the indicated protons in the following compound would appear most downfield in the ¹H NMR spectrum?

A)I
B)II
C)III
D)IV
E)V

Question 29

Which of the indicated protons in the following compound would appear most upfield in the ¹H NMR spectrum?

A)I
B)II
C)III
D)IV
E)I & III

Question 30

How many signals would you expect to find in the ¹H NMR spectrum of the following compound?

A)4
B)5
C)6
D)7
E)9

Question 31

How many signals would you expect to find in the ¹H NMR spectrum of the following compound?

A)4
B)5
C)6
D)7
E)8

Question 32

Which of the following is a correct prediction of the chemical shifts for the signals in the ¹H NMR spectrum for the following compound?

A)I=0.9 ppm,II=2.7 ppm,III=1.2 ppm,IV=0.9 ppm
B)I=1.1 ppm,II=3.2 ppm,III=1.4 ppm,IV=0.9 ppm
C)I=0.9 ppm,II=1.7 ppm,III=1.2 ppm,IV=1.1 ppm
D)I=0.9 ppm,II=1.9 ppm,III=3.4 ppm,IV=0.9 ppm
E)none of these

Question 33

Which of the following is a correct prediction of the chemical shifts for the signals in the ¹H NMR spectrum for the following compound?

A)I=0.9 ppm,II=1.7 ppm,III=3.9 ppm,IV=2.4 ppm
B)I=0.9 ppm,II=1.2 ppm,III=3.7 ppm,IV=1.9 ppm
C)I=0.9 ppm,II=1.7 ppm,III=3.4 ppm,IV=2.4 ppm
D)I=0.9 ppm,II=1.7 ppm,III=3.4 ppm,IV=1.9 ppm
E)none of these

Question 34

Which of the indicated protons in the following compound would appear most downfield in the ¹H NMR spectrum?

A)I
B)II
C)III
D)IV

Question 35

Which of the following is a correct prediction of the chemical shifts for the signals in the ¹H NMR spectrum for the following compound?

A)I=3.9 ppm,II=4.2 ppm,III=2.2 ppm,IV=3.4 ppm
B)I=3.4 ppm,II=2.2 ppm,III=2.2 ppm,IV=3.4 ppm
C)I=3.4 ppm,II=2.2 ppm,III=4.2 ppm,IV=3.4 ppm
D)I=3.4 ppm,II=4.2 ppm,III=4.2 ppm,IV=3.4 ppm
E)none of these

Question 36

How many signals would you expect to find in the ¹H NMR spectrum of the following compound?

A)4
B)5
C)6
D)7
E)8

Question 37

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

Question 38

Predict the chemical shifts for the signals in the ¹H NMR spectrum for the following compound.

Question 39

Predict the chemical shifts for the signals in the ¹H NMR spectrum for the following compound?

Question 40

Which of the following protons appear most upfield in the ¹H NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 41

Determine the multiplicity and predict the chemical shifts of each signal in the expected ¹H NMR spectrum of the following compound.

Question 42

Which of the following compounds will display a singlet,a triplet and a quartet in the ¹H 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

Question 43

Which of the following compounds will display two triplets and a singlet in the ¹H NMR spectrum?

A)CH₃CH(OCH₃)₂
B)CH₃OCH₂CH₂OCH₃
C)CH₃OCH₂CH(OH)CH₃
D)CH₃OCH₂CH₂CH₂CH₂OCH₃
E)none of these

Question 44

How would you use ¹H NMR spectroscopy to distinguish between the following two compounds?

Question 45

Presence of which of the following protons is confirmed by D₂O exchange?

A)OH
B)NH₂
C)CH
D)A & B
E)none of these

Question 46

Determine the multiplicity and predict the chemical shifts of each signal in the expected ¹H NMR spectrum of the following compound.

Question 47

How would you use ¹H NMR spectroscopy to distinguish between the following two compounds?

Question 48

Which of the following is the maximum multiplicity observed for H_b protons in the following compound? Assume that J_ab and J_bc values are different.

A)9
B)12
C)21
D)24
E)none of these

Question 49

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of 2,3-dimethyl-2-pentanol.

Question 50

Which of the following is the maximum multiplicity observed for H_c protons in the following compound? Assume that J_cd and J_cb values are different.

A)5
B)6
C)8
D)12
E)none of these

Question 51

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of the following compound.

Question 52

A compound with a molecular formula C₉H₁₂ has the following ¹H NMR spectrum.Which of the following structures is consistent with this spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 53

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of the following compound.

Question 54

How would you use ¹H NMR spectroscopy to distinguish between the following two compounds?

A)I=3 & II=2 signals
B)I=4 & II=3 signals
C)I=5 & II=3 signals
D)none of these

Question 55

How would you use ¹H NMR spectroscopy to distinguish between the following two compounds?

Question 56

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of the following compound.

Question 57

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of the following compound.

Question 58

Propose a structure for a compound with molecular formula C₅H₁₁Cl,that fits the following spectroscopic data:
¹H NMR: 0.9 $\delta$ (triplet,I=3),1.3 $\delta$ (sextet,I=2),1.5 $\delta$ (quartet,I=2),1.6 $\delta$ (doublet,I=3),3.6 $\delta$ (sextet,I=1)

Question 59

Determine the multiplicity of each signal in the expected ¹H NMR spectrum of the following compound.

Question 60

Determine the multiplicity and predict the chemical shifts of each signal in the expected ¹H NMR spectrum of the following compound.

Question 61

How many signals would you expect to find in the ¹³C NMR spectrum of the following compound?

A)6
B)7
C)8
D)9
E)none of these

Question 62

Propose a structure for a compound with molecular formula C₈H₁₄O₃ that fits the following spectroscopic data.
IR:1820cm^-1,1760cm^-1
1H NMR: 1.0 $\delta$ (triplet,I=6),1.6 $\delta$ (sextet,I=4),2.2 $\delta$ (triplet,I=4)

Question 63

Which of the following ¹³C NMR chemical shifts corresponds to C_a in the following compound?

A)120 ppm
B)145 ppm
C)159 ppm
D)200 ppm
E)none of these

Question 64

Propose a structure for a compound with molecular formula C₁₀H₁₂O that fits the following spectroscopic data.
IR:1680cm^-1
1H NMR: 1.0 $\delta$ (triplet,I=3),1.5 $\delta$ (sextet,I=2),2.6 $\delta$ (triplet,I=4),7.4 $\delta$ (triplet,I=2),7.5 $\delta$ (triplet,I=1),7.9 $\delta$ (doublet,I=2)

Question 65

How many signals would you expect to find in the ¹³C NMR spectrum of the following compound?

A)6
B)7
C)8
D)9
E)none of these

Question 66

How many signals would you expect to find in the ¹³C NMR spectrum of the following compound?

A)2
B)3
C)4
D)5
E)none of these

Question 67

Which of the following carbon atoms will display the signal most downfield in the ¹³C NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 68

A compound with a molecular formula C₁₀H₁₂O₂ has the following HNMR spectrum.Which of the following structures is consistent with this spectrum?

A) I
B) II
C) III
D) IV
E) none of these

Question 69

Which of the following compounds will display four signals in the ¹³C NMR spectrum?

A)2,6-dimethylheptane
B)2,4-dimethylheptane
C)3,5-dimethylheptane
D)4,4-dimethylheptane
E)none of these

Question 70

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

Question 71

Which of the following compounds will not display a carbonyl carbon signal in the DEPT-90 and DEPT-135 ¹³C NMR spectroscopy?

A)I
B)II
C)III
D)II & III
E)none of these

Question 72

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

Question 73

Which of the following compounds is consistent with the following ¹³C NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 74

Which of the following compounds will display five signals in the ¹³C NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 75

A compound with a molecular formula C₈H₁₆O has the following ¹H NMR spectrum.Provide a structure that is consistent with this spectrum?

Question 76

Which of the following display a signal in the DEPT-90 ¹³C NMR spectroscopy?

A)CH₃
B)CH₂
C)CH
D)C
E)none of these

Question 77

Which of the following compounds is consistent with the following ¹³C NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 78

How many signals would you expect to find in the ¹³C NMR spectrum of the following compounds?

A)I-5,II-8
B)I-3,II-6
C)I-4,II-8
D)I-5,II-6
E)none of these

Question 79

Which of the following compounds is consistent with the following ¹³C NMR spectrum?

A)I
B)II
C)III
D)IV
E)none of these

Question 80

Which of the following compounds is consistent with the following ¹³C NMR spectrum?

A)I
B)II
C)III
D)none of these