Question 1

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

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Question 2

How might the proton spectrum of ultrapure dimethylamine, (CH₃)₂NH, differ from the spectrum of this compound to which D₂O has been added?

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Question 3

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

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Question 4

Deduce the structure from the data given: C₈H₁₀O; ¹³C NMR δ (coupling): 140 (s), 128 (d), 126 (d), 122 (d), 60 (t), 15 (q).

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Question 5

Deduce the identity of the compound from the data provided. C₅H₁₀O₂: IR (cm^-1): 2950, 1740; ¹³C NMR (δ, splitting): 15.8 (q), 19.7 (q), 68.4 (d), 195.3 (s)

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Question 6

Can alkenes and aromatics be easily distinguished from each other in an ¹³C NMR spectrum?

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Question 7

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.

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Question 8

Deduce the identity of the compound from the data provided. C₈H₁₃Br: IR (cm^-1): 2950, 2150 ¹H NMR (δ, splitting, integral): 3.5 (t, 2H), 1.8 (t, 2H), 0)9 (s, 9H) ¹³C NMR: 6 signals

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Question 9

What multiplicities are observed in the spin coupled ¹³C NMR spectrum of 2,3-dimethyl-2-butene?

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Question 10

Give one reason why ¹³C NMR is less sensitive than ¹H NMR.

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Question 11

Why is carbon-hydrogen coupling not generally seen in ¹H NMR spectra?

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Question 12

A compound gave a signal at 203 ppm in the ¹³C NMR spectrum. How would it be possible to tell if the compound is an aldehyde or a ketone in a proton-coupled ¹³C NMR spectrum?

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Question 13

Give the structure of a compound that has a formula of C₆H₁₂O and has a triplet (3H, 1.1 ppm), doublet (6H, 1.2 ppm), quartet (2H, 2.4 ppm), and septet (1H, 2.7 ppm)in the ¹H NMR spectrum.

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Question 14

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

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Question 15

Which of the following compounds has a signal disappear when D₂O is added to it, ethyl alcohol or ethyl chloride?

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Question 16

Give the structure of a compound that has a formula of C₄H₇ClO₂ and has a triplet (3H, 1.1 ppm), quintet (2H, 1.2 ppm), triplet (1H, 4.4 ppm), and singlet (1H, 11.6 ppm)in the ¹H NMR spectrum.

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Question 17

Deduce the identity of the compound from the data provided. C₇H₁₂: IR (cm^-1): 3300, 2950, 2220; ¹³C NMR: 5 signals

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The IR spectrum shows a strong absorbance at 3300 cm^-1, which indicates a C-H stretching frequency. The presence of a triple bond in the compound is suggested by the IR absorptions at 2220 cm^-1. The ^13C NMR spectrum shows five signals, indicating five unique carbon environments. The most likely compound that fits these data is 4,4-dimethyl-1-pentyne.

Question 18

Give the structure of a compound that has a formula of C₅H₁₀O_2, and has a triplet (3H, 1.1 ppm), sextet (2H, 1.8 ppm), triplet (2H, 2.3 ppm)and a singlet (3H, 3.8 ppm)in the ¹H NMR spectrum.

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Question 19

Deduce the identity of the compound from the data provided. C₅H₈O₄: IR (cm^-1): 2800-3300 (broad), 2950, 1740 ¹³C NMR (δ, splitting): 17.3 (q), 44.3 (s), 210.5 (s)

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The IR spectrum indicates the presence of a broad O-H stretch (2800-3300 cm^-1), a C-H stretch (2950 cm^-1), and a carbonyl group (1740 cm^-1). The ^13C NMR data shows a quartet at 17.3 ppm (indicative of a CH3 group next to an oxygen), a singlet at 44.3 ppm (indicative of a saturated carbon), and a singlet at 210.5 ppm (indicative of a carbonyl carbon). The structure in option A, which is acetic acid, matches these characteristics, including the presence of a carboxylic acid group (OH attached to a carbonyl carbon), which is consistent with the IR and NMR data provided.

Question 20

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

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Quiz 15: Nmr Spectroscopy

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

How might the proton spectrum of ultrapure dimethylamine, (CH₃)₂NH, differ from the spectrum of this compound to which D₂O has been added?

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

Deduce the structure from the data given: C₈H₁₀O; ¹³C NMR δ (coupling): 140 (s), 128 (d), 126 (d), 122 (d), 60 (t), 15 (q).

Deduce the identity of the compound from the data provided. C₅H₁₀O₂: IR (cm^-1): 2950, 1740; ¹³C NMR (δ, splitting): 15.8 (q), 19.7 (q), 68.4 (d), 195.3 (s)

Can alkenes and aromatics be easily distinguished from each other in an ¹³C NMR spectrum?

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.

Deduce the identity of the compound from the data provided. C₈H₁₃Br: IR (cm^-1) : 2950, 2150 ¹H NMR (δ, splitting, integral) : 3.5 (t, 2H) , 1.8 (t, 2H) , 0) 9 (s, 9H) ¹³C NMR: 6 signals

What multiplicities are observed in the spin coupled ¹³C NMR spectrum of 2,3-dimethyl-2-butene?

Give one reason why ¹³C NMR is less sensitive than ¹H NMR.

Why is carbon-hydrogen coupling not generally seen in ¹H NMR spectra?

A compound gave a signal at 203 ppm in the ¹³C NMR spectrum. How would it be possible to tell if the compound is an aldehyde or a ketone in a proton-coupled ¹³C NMR spectrum?

Give the structure of a compound that has a formula of C₆H₁₂O and has a triplet (3H, 1.1 ppm) , doublet (6H, 1.2 ppm) , quartet (2H, 2.4 ppm) , and septet (1H, 2.7 ppm) in the ¹H NMR spectrum.

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

Which of the following compounds has a signal disappear when D₂O is added to it, ethyl alcohol or ethyl chloride?

Give the structure of a compound that has a formula of C₄H₇ClO₂ and has a triplet (3H, 1.1 ppm) , quintet (2H, 1.2 ppm) , triplet (1H, 4.4 ppm) , and singlet (1H, 11.6 ppm) in the ¹H NMR spectrum.

Deduce the identity of the compound from the data provided. C₇H₁₂: IR (cm^-1) : 3300, 2950, 2220; ¹³C NMR: 5 signals

Give the structure of a compound that has a formula of C₅H₁₀O_2, and has a triplet (3H, 1.1 ppm) , sextet (2H, 1.8 ppm) , triplet (2H, 2.3 ppm) and a singlet (3H, 3.8 ppm) in the ¹H NMR spectrum.

Deduce the identity of the compound from the data provided. C₅H₈O₄: IR (cm^-1) : 2800-3300 (broad) , 2950, 1740 ¹³C NMR (δ, splitting) : 17.3 (q) , 44.3 (s) , 210.5 (s)

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

Quiz 15: Nmr Spectroscopy

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

How might the proton spectrum of ultrapure dimethylamine, (CH3)2NH, differ from the spectrum of this compound to which D2O has been added?

How many distinct carbon signals are expected in the proton-decoupled 13C NMR spectrum of the compound below?

Deduce the structure from the data given: C8H10O; 13C NMR δ (coupling): 140 (s), 128 (d), 126 (d), 122 (d), 60 (t), 15 (q).

Deduce the identity of the compound from the data provided. C5H10O2: IR (cm-1): 2950, 1740; 13C NMR (δ, splitting): 15.8 (q), 19.7 (q), 68.4 (d), 195.3 (s)

Can alkenes and aromatics be easily distinguished from each other in an 13C NMR spectrum?

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.

Deduce the identity of the compound from the data provided. C8H13Br: IR (cm-1) : 2950, 2150 1H NMR (δ, splitting, integral) : 3.5 (t, 2H) , 1.8 (t, 2H) , 0) 9 (s, 9H) 13C NMR: 6 signals

What multiplicities are observed in the spin coupled 13C NMR spectrum of 2,3-dimethyl-2-butene?

Give one reason why 13C NMR is less sensitive than 1H NMR.

Why is carbon-hydrogen coupling not generally seen in 1H NMR spectra?

A compound gave a signal at 203 ppm in the 13C NMR spectrum. How would it be possible to tell if the compound is an aldehyde or a ketone in a proton-coupled 13C NMR spectrum?

Give the structure of a compound that has a formula of C6H12O and has a triplet (3H, 1.1 ppm) , doublet (6H, 1.2 ppm) , quartet (2H, 2.4 ppm) , and septet (1H, 2.7 ppm) in the 1H NMR spectrum.

How many distinct carbon signals are expected in the proton-decoupled 13C NMR spectrum of the compound below?

Which of the following compounds has a signal disappear when D2O is added to it, ethyl alcohol or ethyl chloride?

Give the structure of a compound that has a formula of C4H7ClO2 and has a triplet (3H, 1.1 ppm) , quintet (2H, 1.2 ppm) , triplet (1H, 4.4 ppm) , and singlet (1H, 11.6 ppm) in the 1H NMR spectrum.

Deduce the identity of the compound from the data provided. C7H12: IR (cm-1) : 3300, 2950, 2220; 13C NMR: 5 signals

Give the structure of a compound that has a formula of C5H10O2, and has a triplet (3H, 1.1 ppm) , sextet (2H, 1.8 ppm) , triplet (2H, 2.3 ppm) and a singlet (3H, 3.8 ppm) in the 1H NMR spectrum.

Deduce the identity of the compound from the data provided. C5H8O4: IR (cm-1) : 2800-3300 (broad) , 2950, 1740 13C NMR (δ, splitting) : 17.3 (q) , 44.3 (s) , 210.5 (s)

How many distinct carbon signals are expected in the proton-decoupled 13C NMR spectrum of the compound below?

How might the proton spectrum of ultrapure dimethylamine, (CH₃)₂NH, differ from the spectrum of this compound to which D₂O has been added?

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

Deduce the structure from the data given: C₈H₁₀O; ¹³C NMR δ (coupling): 140 (s), 128 (d), 126 (d), 122 (d), 60 (t), 15 (q).

Deduce the identity of the compound from the data provided. C₅H₁₀O₂: IR (cm^-1): 2950, 1740; ¹³C NMR (δ, splitting): 15.8 (q), 19.7 (q), 68.4 (d), 195.3 (s)

Can alkenes and aromatics be easily distinguished from each other in an ¹³C NMR spectrum?

Deduce the identity of the compound from the data provided. C₈H₁₃Br: IR (cm^-1) : 2950, 2150 ¹H NMR (δ, splitting, integral) : 3.5 (t, 2H) , 1.8 (t, 2H) , 0) 9 (s, 9H) ¹³C NMR: 6 signals

What multiplicities are observed in the spin coupled ¹³C NMR spectrum of 2,3-dimethyl-2-butene?

Give one reason why ¹³C NMR is less sensitive than ¹H NMR.

Why is carbon-hydrogen coupling not generally seen in ¹H NMR spectra?

A compound gave a signal at 203 ppm in the ¹³C NMR spectrum. How would it be possible to tell if the compound is an aldehyde or a ketone in a proton-coupled ¹³C NMR spectrum?

Give the structure of a compound that has a formula of C₆H₁₂O and has a triplet (3H, 1.1 ppm) , doublet (6H, 1.2 ppm) , quartet (2H, 2.4 ppm) , and septet (1H, 2.7 ppm) in the ¹H NMR spectrum.

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?

Which of the following compounds has a signal disappear when D₂O is added to it, ethyl alcohol or ethyl chloride?

Give the structure of a compound that has a formula of C₄H₇ClO₂ and has a triplet (3H, 1.1 ppm) , quintet (2H, 1.2 ppm) , triplet (1H, 4.4 ppm) , and singlet (1H, 11.6 ppm) in the ¹H NMR spectrum.

Deduce the identity of the compound from the data provided. C₇H₁₂: IR (cm^-1) : 3300, 2950, 2220; ¹³C NMR: 5 signals

Give the structure of a compound that has a formula of C₅H₁₀O_2, and has a triplet (3H, 1.1 ppm) , sextet (2H, 1.8 ppm) , triplet (2H, 2.3 ppm) and a singlet (3H, 3.8 ppm) in the ¹H NMR spectrum.

Deduce the identity of the compound from the data provided. C₅H₈O₄: IR (cm^-1) : 2800-3300 (broad) , 2950, 1740 ¹³C NMR (δ, splitting) : 17.3 (q) , 44.3 (s) , 210.5 (s)

How many distinct carbon signals are expected in the proton-decoupled ¹³C NMR spectrum of the compound below?