Deck 13: Nuclear Magnetic Resonance Spectroscopy

Question 1

How many sets of equivalent protons are there in hexane?

A)2
B)3
C)6
D)7

Answer 1

3

Question 2

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of 1-bromo-2-methylpropane?

A)singlet
B)doublet
C)triplet
D)nonet

Answer 2

doublet

Question 3

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2,3-dimethylbutane?

A)two doublets
B)a doublet and a septet
C)a singlet and two doublets
D)a doublet and an octet

Answer 3

two doublets

Question 4

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2-methylpropane?

A)two singlets
B)a singlet and a nonet
C)a singlet and a decet
D)a doublet and a decet

Question 5

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of ethane?

A)singlet
B)doublet
C)triplet
D)quartet

Question 6

Which of the following combinations of peaks appears in the ¹H NMR spectrum of diethyl ether, CH₃CH₂OCH₂CH₃?

A)a triplet and a doublet
B)a quartet and a sextet
C)two singlets
D)a triplet and a quartet

Question 7

Which of the following is not true regarding ¹H NMR spectroscopy?

A)"shielding" leads to peaks at lower values of $\sigma$
B)a "downfield" peak appears at a higher value of $\sigma$
C)" $\sigma$ for a particular proton depends on the magnetic field strength of the instrument used."
D)on a 300 MHz instrument, a proton that adsorbs irradiation at a frequency 1200 Hz higher than the adsorption of TMS appears at $\sigma$ 4 ppm.

Question 8

Which of the following is not true regarding ¹H NMR spectroscopy?

A)a "downfield" peak appears at a lower value of $\delta$
B)on a 300 MHz instrument, a proton that adsorbs irradiation at a frequency 900 Hz higher than the adsorption of TMS appears at $\delta$ 3 ppm.
C)" $\delta$ for a particular proton is independent of the magnetic field strength of the instrument used."
D)"deshielding" leads to peaks at higher values of $\delta$

Question 9

Which feature in the ¹H NMR spectrum provides information about the relative number of each type of proton in a compound?

A)number of signals
B)integral
C)splitting
D)chemical shift

Question 10

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,4-dimethyoxyethane, CH₃OCH₂CH₂CH₂CH₂OCH₃?

A)three singlets
B)a singlet, a triplet, and a quintet
C)a singlet and two triplets
D)a doublet and a triplet

Question 11

What is the appearance of the signal corresponding to the CH₂ protons in the ¹H NMR spectrum of ethyl methyl ether, CH₃CH₂OCH₃?

A)a doublet
B)a triplet
C)a quartet
D)a septet

Question 12

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,2-dimethyoxyethane, CH₃OCH₂CH₂OCH₃?

A)two singlets
B)a singlet and a triplet
C)a singlet and two triplets
D)a doublet and a triplet

Question 13

Which feature in the ¹H NMR spectrum provides information about the number of neighboring protons of each proton in the compound?

A)number of signals
B)integral
C)multiplicity
D)chemical shift

Question 14

Which C₄H₉Br compound gives a triplet at approximately 3.5 ppm in the ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 15

How many sets of equivalent protons are there in 3-methylhexane?

A)2
B)3
C)6
D)7

Question 16

Which feature in the ¹H NMR spectrum provides information about the electronic environment of the protons in a compound?

A)number of signals
B)integral
C)splitting
D)chemical shift

Question 17

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of propane?

A)singlet
B)doublet
C)triplet
D)quartet

Question 18

How many sets of equivalent protons are there in 2-methylhexane?

A)2
B)3
C)6
D)7

Question 19

Which of the following combinations of peaks appears in the ¹H NMR spectrum of butane?

A)a triplet and a doublet
B)a triplet and a quartet
C)a triplet and a sextet
D)two singlets

Question 20

Which feature in the ¹H NMR spectrum provides information about the number of types of different protons in a compound?

A)number of signals
B)integral
C)splitting
D)chemical shift

Question 21

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 1,3-dibromobenzene?

A)1
B)2
C)3
D)4

Question 22

What is the relative area of the six peaks in a sexet in an ¹H NMR spectrum?

A)1:2:3:3:2:1
B)1:3:6:6:3:1
C)1:5:10:10:5:1
D)1:6:15:15:6:1

Question 23

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 2-bromotoluene?

A)3
B)4
C)5
D)7

Question 24

Which of the protons in the following molecule appear at the highest $\delta$ -value in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 25

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 4-bromotoluene?

A)3
B)4
C)5
D)7

Question 26

Which of the protons in the following molecule appear at the highest $\delta$ -value in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 27

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 28

Which C₄H₉Br compound(s) gives a ¹³C NMR spectrum consisting of four signals?

A)only 1
B)only 1 and 2
C)only 2 and 3
D)1, 2, 3 and 4

Question 29

Which C₄H₉Br compound gives a doublet at approximately 3.3 ppm in the ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 30

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 1,2-dibromobenzene?

A)1
B)2
C)3
D)4

Question 31

What is the relative area of the six peaks in a septet in an ¹H NMR spectrum?

A)1:2:3:4:3:2:1
B)1:3:6:12:6:3:1
C)1:6:15:30:15:6:1
D)1:6:15:20:15:6:1

Question 32

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 33

Which of the protons in the following molecule appear at the highest $\delta$ -value in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 34

How many signals appear in proton-decoupled ¹³C NMR spectrum of 3,4-dimethylhexane?

A)3
B)4
C)5
D)6

Question 35

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 1,4-dibromobenzene?

A)1
B)2
C)3
D)4

Question 36

Which of the following compounds gives a ¹H NMR spectrum consisting of two singlets and a ¹³C NMR consisting of consisting of three signals?

A)only i
B)only iii
C)only ii and iii
D)only ii, iii and iv

Question 37

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 38

Which C₄H₉Br compound(s) gives a ¹³C NMR spectrum consisting of two signals?

A)only 1
B)only 2
C)only 2 and 3
D)1, 2, 3 and 4

Question 39

How many signals appear in proton-decoupled ¹³C NMR spectrum of 2,5-dimethylhexane?

A)3
B)4
C)5
D)6

Question 40

How many signals appear in the proton-decoupled ¹³C NMR spectrum of 3-bromotoluene?

A)3
B)4
C)5
D)7

Question 41

What is the hydrogen deficiency index for a compound with a molecular formula of C₆H₆Br₂?

A)1
B)2
C)3
D)4

Question 42

Which of the following compounds would give a ¹H NMR spectrum consisting of two singlets and a ¹³C NMR consisting of consisting of three signals?

A)only i
B)only iii
C)only i and iii
D)iii and iv

Question 43

How many signals appear in the proton-decoupled ¹³C NMR spectrum of the following compound?

A)7
B)8
C)9
D)11

Question 44

What is the hydrogen deficiency index for a compound with a molecular formula of C₁₂H₁₆O?

A)2
B)4
C)5
D)6

Question 45

The coupling constant, J, between the protons of chloroethane is 7 Hz when the spectrum is obtained 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

Question 46

Which of the following is true for pair of homotropic protons?
1)They will appear at the same chemical shift in an achiral (i.e., nonchiral) environment
2)They will appear at the same chemical shifts in a chiral environment

A)only 1
B)only 2
C)neither 1 nor 2
D)both 1 and 2

Question 47

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

A)1,1-dibromopropane
B)1,2-dibromopropane
C)1,3-dibromopropane
D)2,2-dibromopropane

Question 48

Which of the following compounds gives a ¹H NMR spectrum consisting of only a singlet, triplet and quintet?

A)CH₃OCH₂CH₂CH₂CH₂OH
B)CH₃OCH₂CH₂OCH₂CH₃
C)CH₃OCH₂CH₂CH₂OCH₃
D)CH₃OCH₂CH(CH₃)OCH₃

Question 49

Which of the following compounds gives a ¹H NMR spectrum consisting of only two singlets?

A)CH₃OCH₂CH₂OCH₂CH₃
B)CH₃OCH₂CH₂CH₂CH₂OH
C)CH₃OC(CH₃)₂OCH₃
D)CH₃OCH₂CH(CH₃)OCH₃

Question 50

Which of the following is true for pair of enantiotopic protons?
1)They will appear at the same chemical shift in an achiral (i.e., nonchiral environment)
2)They will appear at the same chemical shifts in a chiral environment

A)only 1
B)only 2
C)neither 1 nor 2
D)both 1 and 2

Question 51

Which of the protons in the following molecule appear at the highest $\delta$ -value in the ¹H NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 52

Which of the following compounds have homotopic protons?
1)propane
2)butane
3)2-methylpropane

A)only 1
B)only 2
C)only 1 and 2
D)1, 2 and 3

Question 53

How many signals appear in the proton-decoupled ¹³C NMR spectrum of the following compound?

A)6
B)7
C)8
D)11

Question 54

Which of the carbon atoms in the following molecule appears furthest downfield in the ¹³C NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 55

The chemical shift of the protons of acetone, CH₃COCH₃, is 2.1 ppm when the spectrum is obtained at 250 MHz. What is the chemical shift of these protons when the spectrum is acquired at 500 MHz?

A)1.05 ppm
B)2.1 ppm
C)4.2 ppm
D)8.4 ppm

Question 56

Which of the carbon atoms in the molecule appears furthest downfield in the ¹³C NMR spectrum?

A)i
B)ii
C)iii
D)iv

Question 57

Which of the following compounds have enantiotopic protons?
1)propane
2)butane
3)2-methylpropane

A)only 1
B)only 2
C)only 1 and 2
D)1, 2 and 3

Question 58

Which of the following compounds gives a ¹H NMR spectrum consisting of only two triplets and a singlet?

A)CH₃CH(OCH₃)₂
B)CH₃OCH₂CH₂CH₂CH₂OCH₃
C)CH₃OCH₂CH₂OCH₃
D)CH₃OCH₂CH(OH)CH₃

Question 59

What is the hydrogen deficiency index for a compound with a molecular formula of C₆H₁₁N?

A)1
B)2
C)3
D)4

Question 60

What is the hydrogen deficiency index for a compound with a molecular formula of C₁₀H₁₆O₂?

A)1
B)2
C)3
D)4

Question 61

For each of the compounds below tell how many signals you would expect the molecule to have in its normal, broadband hydrogen-decoupled ¹³C NMR spectra. Enter the numerical value in the blank provided to the left of the structure.
_______

Question 62

For each of the compounds below tell how many signals you would expect the molecule to have in its normal, broadband hydrogen-decoupled ¹³C NMR spectra. Enter the numerical value in the blank provided to the left of the structure.
_______

Question 63

Which C₈H₁₀ compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 64

The following compound will have a ¹H NMR spectrum that consists of: two triplets and a singlet, area ratio 3:3:4.

Question 65

Consider the compound shown below. The above compound would produce a signal further downfield in a ¹³C NMR spectrum than

Question 66

Which C₈H₁₀ compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 67

All of the following compound produce only singlets in a ¹H NMR spectrum.

Question 68

Which of the following is true for pair of diastereotopic protons?
1)They will appear at the same chemical shift in an achiral (i.e., nonchiral environment)
2)They will appear at the same chemical shifts in a chiral environment

A)only 1
B)only 2
C)neither 1 nor 2
D)both 1 and 2

Question 69

All of the following would produce nuclear magnetic resonance: ²H, ¹⁴N, ¹⁶O, and ¹⁹F.

Question 70

Which C₉H₁₀O compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 71

Which C₆H₁₂O₂ compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 72

Which C₆H₁₂O₂ compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 73

Predict the splitting of each of the numbered hydrogen atoms in the structure below in a ¹H NMR spectrum. Identify as singlet, doublet, triplet, quartet, quintet, sextet, septet, .... Place the correct splitting in the blank to the left of the number.
______ 1

Question 74

The splitting of signals in the ¹H NMR spectrum provides information about the number of neighboring protons of each proton in the compound.

Question 75

For each of the compounds below tell how many signals you would expect the molecule to have in its normal, broadband hydrogen-decoupled ¹³C NMR spectra. Enter the numerical value in the blank provided to the left of the structure.
_______

Question 76

For each of the compounds below tell how many signals you would expect the molecule to have in its normal, broadband hydrogen-decoupled ¹³C NMR spectra. Enter the numerical value in the blank provided to the left of the structure.
_______

Question 77

For each of the compounds below tell how many signals you would expect the molecule to have in its normal, broadband hydrogen-decoupled ¹³C NMR spectra. Enter the numerical value in the blank provided to the left of the structure.
_______

Question 78

Consider the following structure. If the proton attached to C2 in 1,1,2-tribromopropane is coupled with the protons on C1 (J = 3.6 Hz) and C3 (J = 6.8), the tree diagram of the C2 proton is shown below.

Question 79

Which C₉H₁₀O compound gives the following ¹H NMR spectrum?

A)1
B)2
C)3
D)4

Question 80

Nuclear magnetic resonance spectroscopy provides information about a molecule's carbon-hydrogen framework.