Deck 13: Nuclear Magnetic Resonance Spectroscopy

Question 1

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

Answer 1

a singlet and two triplets

Question 2

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

Answer 2

number of signals

Question 3

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

Answer 3

multiplicity

Question 4

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

Question 5

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 6

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 7

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 8

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

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

Question 9

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 10

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

A) "shielding" leads to peaks at lower values of δ
B) a "downfield" peak appears at a higher value of δ
C) δ 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 δ 4 ppm.

Question 11

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 12

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 13

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

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

Question 14

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 15

How many sets of equivalent protons are there in hexane?

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

Question 16

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 17

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 18

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

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

Question 19

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

Question 20

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 21

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

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

Question 22

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 23

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum? $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ O
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ ||
$\mathrm{H}_{3} \mathrm{C}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{C}-\mathrm{H}$
$\quad$ i $\quad$$\quad$$\quad$$\quad$$\quad$ ii $\quad$$\quad$ iii $\quad$$\quad$$\quad$ iv

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

Question 24

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 25

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

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

Question 26

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

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

Question 27

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum? $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{Cl}$
$\quad$ i $\quad$$\quad$$\quad$ ii $\quad$$\quad$ iii $\quad$$\quad$ iv

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

Question 28

Which of the protons in the following molecule appear furthest downfield in the ¹H NMR spectrum? $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ O
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ ||
$\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{C}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{3}$
$\quad$ i $\quad$$\quad$$\quad$ ii $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ iii $\quad$$\quad$ iv

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

Question 29

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

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

Question 30

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 31

Which of the protons in the following molecule appear at the highest ?-value in the ¹H NMR spectrum? $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ O
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ ||
$\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{C}-\mathrm{CH}_{3}$
$\quad$ i $\quad$$\quad$$\quad$ ii $\quad$$\quad$ iii $\quad$$\quad$$\quad$ iv

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

Question 32

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

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

Question 33

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 34

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

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

Question 35

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

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

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

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 38

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

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

Question 39

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

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

Question 40

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

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

Question 41

Which C₉H₁₀O compound gives the following ¹H NMR spectrum?

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

Question 42

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

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

Question 43

Which of the protons in the following molecule appear at the highest ?-value in the ¹H NMR spectrum? $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ O
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ ||
$\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{C}-\mathrm{H}$
$\quad$ i $\quad$$\quad$$\quad$ ii $\quad$$\quad$ iii $\quad$$\quad$$\quad$ iv

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

Question 44

Which C₉H₁₀O compound gives the following ¹H NMR spectrum?

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

Question 45

Which C₆H₁₂O₂ compound gives the following ¹H NMR spectrum?

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

Question 46

Which C₆H₁₂O₂ compound gives the following ¹H NMR spectrum?

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

Question 47

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 48

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

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

Question 49

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

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

Question 50

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 51

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 52

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 53

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

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

Question 54

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 55

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

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

Question 56

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 57

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 58

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 59

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 60

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

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

Question 61

All of the following compound produce only singlets in a ¹H NMR spectrum. $\quad$$\quad$$\quad$$\quad$$\mathrm{CH}_{3}$
$\quad$$\quad$$\quad$$\quad$$\quad$ |
$\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CCCH}_{3}$
$\quad$$\quad$$\quad$$\quad$$\quad$ |
$\quad$$\quad$$\quad$$\quad$$\mathrm{CH}_{3}$

Question 62

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 63

Which C₈H₁₀ compound gives the following ¹H NMR spectrum?

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

Question 64

Which C₈H₁₀ compound gives the following ¹H NMR spectrum?

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

Question 65

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 66

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

Question 67

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 68

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

Question 69

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 70

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 71

Consider the following structure. Answer the following questions by placing the appropriate number in the blank to the left.
_____The number of nonequivalent hydrogen atoms in this compound.

Question 72

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 73

Identify the ratio of peak areas upon integration of the ¹H NMR spectrum for A, B, and C respectively. Enter the numbers separated by colons.

Question 74

Consider the following structure. Answer the following questions by placing the appropriate number in the blank to the left.
_____The number of signals in the hydrogen-decoupled ¹³C NMR of this compound.

Question 75

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

Question 76

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

Question 77

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 78

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 79

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 80

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