Question 1

Electromagnetic radiation in the ________ region is used in 1H NMR spectroscopy.

Accepted Answer

A)  radio wave 
B)  ultraviolet 
C)  infrared 
D)  microwave 
E)  X-ray 
A)  radio wave 
B)  ultraviolet 
C)  infrared 
D)  microwave 
E)  X-ray

Question 2

A compound (C5H8O) shows IR absorptions at 3600 and 3300 cm-1. Its 1H NMR spectrum contained singlets at   and 2.9 (broad) (ppm) in a ratio of 6:1:1. Name this compound.

Accepted Answer

2-methylbu

Question 3

Deduce the identity of the following compound from the 1H NMR data given.
C4H7BrO: δ 2.2 (3H, singlet), 3.5 (2H, triplet), 4.5 (2H, triplet) (ppm)

Accepted Answer

Question 4

Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of CH3CH2OCH3.

Accepted Answer

3 signals: (3H, trip

Question 5

If a signal is observed in the 170 to 200 ppm range in a C-13 NMR spectrum, what is the most likely type of functional group associated with that carbon atom?

Accepted Answer

A)  carbonyl carbon 
B)  allylic carbon 
C)  aromatic carbon 
D)  carbon/carbon triple bond 
E)  carbon/carbon double bond 
A)  carbonyl carbon 
B)  allylic carbon 
C)  aromatic carbon 
D)  carbon/carbon triple bond 
E)  carbon/carbon double bond

Question 6

What three-word term is abbreviated NMR?

Accepted Answer

nuclear ma

Question 7

The 1H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

Accepted Answer

A fast exchange of the hydroxy

Question 8

Predict the number of signals expected in the proton spin decoupled 13C spectrum of

Accepted Answer

Question 9

Predict the number of signals expected (disregarding splitting) in the 1H NMR spectrum of the compound shown below.

Accepted Answer

Question 10

Deduce the identity of the following compound from the spectral data given.
C8H10: 1H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970,   MS, m/z 91

Accepted Answer

Question 11

Deduce the identity of the following compound from the NMR data given.
C4H6O2: 1H NMR, δ 2.28 (2H, multiplet), 2.50 (2H, triplet), 4.35 (2H, triplet);
13C NMR, δ 177.81 (singlet), 68.58 (triplet), 27.70 (triplet), 22.17 (triplet) (ppm)

Accepted Answer

Question 12

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Question 13

What is the relationships between Ha and Hb in the following structure?

Accepted Answer

A)  homeotopic 
B)  enantiotopic 
C)  diastereotopic 
D)  none of the previous 
A)  homeotopic 
B)  enantiotopic 
C)  diastereotopic 
D)  none of the previous

Question 14

Predict the number of signals expected in the proton spin decoupled 13C spectrum of 3-hexanone, CH3CH2COCH2CH2CH3.

Accepted Answer

Question 15

Provide a structure that is consistent with the data below.
C4H8O
IR (cm-1): 2950
1H NMR ( d): 3.2 (4H, t), 1.2 (4H, t)
13C NMR (d ): 68 (t), 27 (t)

Accepted Answer

Question 16

Predict the number of signals expected (disregarding splitting) in the 1H spectrum of m-xylene (1,3-dimethylbenzene).

Accepted Answer

Question 17

Which of the following reasons best explains why aromatic protons have a larger chemical shift than protons one carbon removed from a halogen?

Accepted Answer

A)  An aromatic ring is more electron withdrawing than a halogen. 
B)  A halogen is more electron withdrawing than an aromatic ring. 
C)  Electron movement induces a magnetic field opposing the external field. 
D)  Electron movement induces a magnetic field reinforcing the external field. 
A)  An aromatic ring is more electron withdrawing than a halogen. 
B)  A halogen is more electron withdrawing than an aromatic ring. 
C)  Electron movement induces a magnetic field opposing the external field. 
D)  Electron movement induces a magnetic field reinforcing the external field.

Question 18

In the 1H NMR spectrum of bromoethane the methylene group is split into a quartet by the α and β nuclear spins of the protons on the neighboring methyl group. If the external magnetic field, B∘, directs upward, which sequence of nuclear spins contributes to the second farthest peak down field within the spin-spin splitting pattern?

Accepted Answer

A)  ↑↓↓ 
B)  ↑↓↑ 
C)  ↑↑↑ 
D)  ↓↓↓ 
E)  ↑↑↓↓ 
A)  ↑↓↓ 
B)  ↑↓↑ 
C)  ↑↑↑ 
D)  ↓↓↓ 
E)  ↑↑↓↓

Question 19

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Accepted Answer

Question 20

Provide a structure that is consistent with the data below.
C9H9N
IR (cm-1): 3050, 2950, 2240, 1630
1H NMR ( d): 7.5 (2H, d), 7.1 (2H, d), 2.3 (2H, q), 0.9 (3H, t)
13C NMR (d ): 137 (s), 130, (s), 126 (d), 122 (d), 95 (s), 25 (t), 15 (q)

Accepted Answer

Exam 13: Nuclear Magnetic Resonance Spectroscopy

Electromagnetic radiation in the ________ region is used in 1H NMR spectroscopy.

A compound (C5H8O) shows IR absorptions at 3600 and 3300 cm-1. Its 1H NMR spectrum contained singlets at and 2.9 (broad) (ppm) in a ratio of 6:1:1. Name this compound.

Deduce the identity of the following compound from the 1H NMR data given. C4H7BrO: δ 2.2 (3H, singlet), 3.5 (2H, triplet), 4.5 (2H, triplet) (ppm)

Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of CH3CH2OCH3.

If a signal is observed in the 170 to 200 ppm range in a C-13 NMR spectrum, what is the most likely type of functional group associated with that carbon atom?

What three-word term is abbreviated NMR?

The 1H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

Predict the number of signals expected in the proton spin decoupled 13C spectrum of

Predict the number of signals expected (disregarding splitting) in the 1H NMR spectrum of the compound shown below.

Deduce the identity of the following compound from the spectral data given. C8H10: 1H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970, MS, m/z 91

Deduce the identity of the following compound from the NMR data given. C4H6O2: 1H NMR, δ 2.28 (2H, multiplet), 2.50 (2H, triplet), 4.35 (2H, triplet); 13C NMR, δ 177.81 (singlet), 68.58 (triplet), 27.70 (triplet), 22.17 (triplet) (ppm)

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

What is the relationships between Ha and Hb in the following structure?

Predict the number of signals expected in the proton spin decoupled 13C spectrum of 3-hexanone, CH3CH2COCH2CH2CH3.

Provide a structure that is consistent with the data below. C4H8O IR (cm-1): 2950 1H NMR ( d): 3.2 (4H, t), 1.2 (4H, t) 13C NMR (d ): 68 (t), 27 (t)

Predict the number of signals expected (disregarding splitting) in the 1H spectrum of m-xylene (1,3-dimethylbenzene).

Which of the following reasons best explains why aromatic protons have a larger chemical shift than protons one carbon removed from a halogen?

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Provide a structure that is consistent with the data below. C9H9N IR (cm-1): 3050, 2950, 2240, 1630 1H NMR ( d): 7.5 (2H, d), 7.1 (2H, d), 2.3 (2H, q), 0.9 (3H, t) 13C NMR (d ): 137 (s), 130, (s), 126 (d), 122 (d), 95 (s), 25 (t), 15 (q)

Introduction and Review

Structure and Properties of Organic Molecules

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides: Nucleophilic Substitution and Elimination

Structure and Synthesis of Alkenes

Reactions of Alkenes

Alkynes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Electromagnetic radiation in the ________ region is used in ¹H NMR spectroscopy.

A compound (C₅H₈O) shows IR absorptions at 3600 and 3300 cm^-1. Its ¹H NMR spectrum contained singlets at and 2.9 (broad) (ppm) in a ratio of 6:1:1. Name this compound.

Deduce the identity of the following compound from the ¹H NMR data given. C₄H₇BrO: δ 2.2 (3H, singlet), 3.5 (2H, triplet), 4.5 (2H, triplet) (ppm)

Predict the number of signals expected, their splitting, and their relative area in the ¹H NMR spectrum of CH₃CH₂OCH₃.

The ¹H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

Predict the number of signals expected in the proton spin decoupled ¹³C spectrum of

Predict the number of signals expected (disregarding splitting) in the ¹H NMR spectrum of the compound shown below.

Deduce the identity of the following compound from the spectral data given. C₈H₁₀: ¹H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970, MS, m/z 91

Deduce the identity of the following compound from the NMR data given. C₄H₆O₂: ¹H NMR, δ 2.28 (2H, multiplet), 2.50 (2H, triplet), 4.35 (2H, triplet); ¹³C NMR, δ 177.81 (singlet), 68.58 (triplet), 27.70 (triplet), 22.17 (triplet) (ppm)

How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

Predict the number of signals expected in the proton spin decoupled ¹³C spectrum of 3-hexanone, CH₃CH₂COCH₂CH₂CH₃.

Provide a structure that is consistent with the data below. C₄H₈O IR (cm^-1): 2950 ¹H NMR ( d): 3.2 (4H, t), 1.2 (4H, t) ¹³C NMR (d ): 68 (t), 27 (t)

Predict the number of signals expected (disregarding splitting) in the ¹H spectrum of m-xylene (1,3-dimethylbenzene).

Predict the number of signals expected in the proton spin decoupled ¹³C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Provide a structure that is consistent with the data below. C₉H₉N IR (cm^-1): 3050, 2950, 2240, 1630 ¹H NMR ( d): 7.5 (2H, d), 7.1 (2H, d), 2.3 (2H, q), 0.9 (3H, t) ¹³C NMR (d ): 137 (s), 130, (s), 126 (d), 122 (d), 95 (s), 25 (t), 15 (q)