Question 1

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

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  5 
E)  6 
A)  2 
B)  3 
C)  4 
D)  5 
E)  6

Question 2

Which of the structures shown below is consistent with the C-13 NMR (off resonance splitting for each peak is shown as a table within the figure) and H-NMR spectra? (formula = C9H11OBr)

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 3

What type of carbon environment does not generate a signal in the DEPT-90 spectrum and gives a negative signal in the DEPT-135 spectrum?

Accepted Answer

A)  quaternary 
B)  methine 
C)  methylene 
D)  methyl 
E)  carbonyl 
A)  quaternary 
B)  methine 
C)  methylene 
D)  methyl 
E)  carbonyl

Question 4

Provide a structure that is consistent with the data below.
C7H16O
IR (cm-1): 3200-3600 (broad), 2950
1H NMR ( d): 2.8 (1H, broad s), 1.0 (6H, s), 0.9 (9H, s)
13C NMR (d ): 68 (s), 39 (s), 16 (q), 13 (q)

Accepted Answer

Question 5

Predict the number of distinct quartets expected in the off-resonance decoupled 13C NMR spectrum of the compound shown below.

Accepted Answer

Question 6

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

Accepted Answer

Question 7

What is the approximate chemical shift of an alkynyl carbon in 13C NMR spectroscopy?

Accepted Answer

A)  10 ppm 
B)  30 ppm 
C)  70 ppm 
D)  120 ppm 
E)  200 ppm 
A)  10 ppm 
B)  30 ppm 
C)  70 ppm 
D)  120 ppm 
E)  200 ppm

Question 8

Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of (CH3)3CCHO.

Accepted Answer

2 signals:

Question 9

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

Accepted Answer

Question 10

A nucleus with an ________ atomic number or an ________ mass number has a nuclear spin that can be observed by the NMR spectrometer.

Accepted Answer

A)  even, odd 
B)  odd, even 
C)  odd, odd 
D)  even, even 
A)  even, odd 
B)  odd, even 
C)  odd, odd 
D)  even, even

Question 11

Deduce the identity of the following compound from the spectral data given.
C5H10O: 1H NMR, δ 1.2 (6H, doublet), 2.1 (3H, singlet), 2.8 (1H, septet) (ppm); IR, 2980, 1710 cm-1; MS, m/z 71, 43

Accepted Answer

Question 12

Predict the number of distinct quartets expected in the off-resonance decoupled 13C NMR spectrum of the compound shown below.

Accepted Answer

Question 13

The chair form of cyclohexane has protons in two distinct environments, axial and equatorial. When the proton NMR of cyclohexane is run on a 100-MHz instrument at 23°C, only one signal for the compound is observed. Explain this apparent contradiction.

Accepted Answer

Axial and equatorial positions are being

Question 14

Provide a structure that is consistent with the data below.
C6H10
IR (cm-1): 2950, 2230
1H NMR ( d): 2.0 (1H, septet), 1.8 (3H, s), 0.9 (6H, d)
13C NMR (d ): 78 (s), 72 (s), 45 (d), 18 (q), 15 (q)

Accepted Answer

Question 15

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

Accepted Answer

Question 16

Deduce the identity of the following compound from the 1H NMR data given.
C6H8O4: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

Accepted Answer

Question 17

An NMR spectrometer that operates at a frequency of 60 MHz for 13C NMR spectra, operates at what frequency for 1H NMR spectra?

Accepted Answer

A)  15 MHz 
B)  30 MHz 
C)  60 MHz 
D)  120 MHz 
E)  240 MHz 
A)  15 MHz 
B)  30 MHz 
C)  60 MHz 
D)  120 MHz 
E)  240 MHz

Question 18

How might the two trimethylcyclohexane isomers shown below be most readily distinguished using NMR?

Accepted Answer

Number of

Question 19

Given that compound X has a molecular formula of C6H10O2, gave three peaks in its 13C NMR spectrum (14, 63 and 158 ppm) and two peaks in its 1H NMR spectrum (1.4, triplet and 4.3 ppm, quartet), provide a structure for compound X.

Accepted Answer

Question 20

Deduce the identity of the following compound from the 1H NMR data given.
C9H10O2: δ 2.2 (3H, singlet), 5.0 (2H, singlet), 7.2 (5H, singlet) (ppm)

Accepted Answer

Exam 13: Nuclear Magnetic Resonance Spectroscopy

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

Which of the structures shown below is consistent with the C-13 NMR (off resonance splitting for each peak is shown as a table within the figure) and H-NMR spectra? (formula = C9H11OBr)

What type of carbon environment does not generate a signal in the DEPT-90 spectrum and gives a negative signal in the DEPT-135 spectrum?

Provide a structure that is consistent with the data below. C7H16O IR (cm-1): 3200-3600 (broad), 2950 1H NMR ( d): 2.8 (1H, broad s), 1.0 (6H, s), 0.9 (9H, s) 13C NMR (d ): 68 (s), 39 (s), 16 (q), 13 (q)

Predict the number of distinct quartets expected in the off-resonance decoupled 13C NMR spectrum of the compound shown below.

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

What is the approximate chemical shift of an alkynyl carbon in 13C NMR spectroscopy?

Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of (CH3)3CCHO.

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

A nucleus with an ________ atomic number or an ________ mass number has a nuclear spin that can be observed by the NMR spectrometer.

Deduce the identity of the following compound from the spectral data given. C5H10O: 1H NMR, δ 1.2 (6H, doublet), 2.1 (3H, singlet), 2.8 (1H, septet) (ppm); IR, 2980, 1710 cm-1; MS, m/z 71, 43

Predict the number of distinct quartets expected in the off-resonance decoupled 13C NMR spectrum of the compound shown below.

The chair form of cyclohexane has protons in two distinct environments, axial and equatorial. When the proton NMR of cyclohexane is run on a 100-MHz instrument at 23°C, only one signal for the compound is observed. Explain this apparent contradiction.

Provide a structure that is consistent with the data below. C6H10 IR (cm-1): 2950, 2230 1H NMR ( d): 2.0 (1H, septet), 1.8 (3H, s), 0.9 (6H, d) 13C NMR (d ): 78 (s), 72 (s), 45 (d), 18 (q), 15 (q)

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

Deduce the identity of the following compound from the 1H NMR data given. C6H8O4: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

An NMR spectrometer that operates at a frequency of 60 MHz for 13C NMR spectra, operates at what frequency for 1H NMR spectra?

How might the two trimethylcyclohexane isomers shown below be most readily distinguished using NMR?

Given that compound X has a molecular formula of C6H10O2, gave three peaks in its 13C NMR spectrum (14, 63 and 158 ppm) and two peaks in its 1H NMR spectrum (1.4, triplet and 4.3 ppm, quartet), provide a structure for compound X.

Deduce the identity of the following compound from the 1H NMR data given. C9H10O2: δ 2.2 (3H, singlet), 5.0 (2H, singlet), 7.2 (5H, singlet) (ppm)

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

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

Which of the structures shown below is consistent with the C-13 NMR (off resonance splitting for each peak is shown as a table within the figure) and H-NMR spectra? (formula = C₉H₁₁OBr)

Provide a structure that is consistent with the data below. C₇H₁₆O IR (cm^-1): 3200-3600 (broad), 2950 ¹H NMR ( d): 2.8 (1H, broad s), 1.0 (6H, s), 0.9 (9H, s) ¹³C NMR (d ): 68 (s), 39 (s), 16 (q), 13 (q)

Predict the number of distinct quartets expected in the off-resonance decoupled ¹³C NMR spectrum of the compound shown below.

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

What is the approximate chemical shift of an alkynyl carbon in ¹³C NMR spectroscopy?

Predict the number of signals expected, their splitting, and their relative area in the ¹H NMR spectrum of (CH₃)₃CCHO.

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

A nucleus with an atomic number or an mass number has a nuclear spin that can be observed by the NMR spectrometer.

Deduce the identity of the following compound from the spectral data given. C₅H₁₀O: ¹H NMR, δ 1.2 (6H, doublet), 2.1 (3H, singlet), 2.8 (1H, septet) (ppm); IR, 2980, 1710 cm^-1; MS, m/z 71, 43

Predict the number of distinct quartets expected in the off-resonance decoupled ¹³C NMR spectrum of the compound shown below.

Provide a structure that is consistent with the data below. C₆H₁₀ IR (cm^-1): 2950, 2230 ¹H NMR ( d): 2.0 (1H, septet), 1.8 (3H, s), 0.9 (6H, d) ¹³C NMR (d ): 78 (s), 72 (s), 45 (d), 18 (q), 15 (q)

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

Deduce the identity of the following compound from the ¹H NMR data given. C₆H₈O₄: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

An NMR spectrometer that operates at a frequency of 60 MHz for ¹³C NMR spectra, operates at what frequency for ¹H NMR spectra?

Given that compound X has a molecular formula of C₆H₁₀O₂, gave three peaks in its ¹³C NMR spectrum (14, 63 and 158 ppm) and two peaks in its ¹H NMR spectrum (1.4, triplet and 4.3 ppm, quartet), provide a structure for compound X.

Deduce the identity of the following compound from the ¹H NMR data given. C₉H₁₀O₂: δ 2.2 (3H, singlet), 5.0 (2H, singlet), 7.2 (5H, singlet) (ppm)