Organic Chemistry Questions and Answers – Nuclear Magnetic Resonance

1 Which of the following organic compound with molecular formula C3H C12 exhibits only one signal in the IH NMR spectrum?

A 2, 2-dichloropropane

B 1, 2-dichloropropane

C 1, 3-dichloropropane

D 1, 1-dichloropropane

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Answer: 2, 2-dichloropropane

2 The 1H NMR spectrum of CH₃OCHCICH₂Cl will exhibit ________

A A three proton doublet. One proton singlet and a two proton doublet

B A three proton singlet. One proton singlet and a two proton doublet

C A three proton singlet. One proton triplet and a two proton doublet

D A three proton triplet. One proton triplet and a two proton triplet

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Answer: A three proton singlet. One proton triplet and a two proton doublet

3 Which of the following 1_H-NMR spectrum of compound with molecular formula C₄H₉NO₂ shows delta 5.30 (broad, IH), 4.10(q, 2H), 2.80 (d, 3H), 1.20 (t, 3H) ppm?

A CH₃NHCOOCH₂CH₃

B CH₃CH₂NHCOOCH₃

C CH₃OCH₂CONHCH₃

D CH₃CH₂OCH₂CONH₂

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Answer: CH₃NHCOOCH₂CH₃

4 Which of the following has three types of hydrogens in the following compounds?

A Br-CH = CH₂

B CH₃ – CH₂ – CH₃

C C₆H₅CH₂

D CH₃– CH₂ – CH(CH₃) – N0₂

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Answer: Br-CH = CH₂

5 Which of the compound show only one signal is present in the PMR spectra?

A C₃H₄, C₃H₆

B C₄H₆, C₅H₁₂

C C₈H₁₈, C₂H₆O

D All of the mentioned

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Answer: All of the mentioned

6 How many Hertz does 1 ppm correspond to for an PMR spectrometer operating at a radio frequency of 60 MHz and 100 MHz?

A 6 Hz, 10 Hz

B 60 Hz, 100 Hz

C 100 Hz, 60 Hz

D 10Hz, 100Hz

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Answer: 60 Hz, 100 Hz

7 Compound C₄H₁₀O gave PMR spectrum consisting of two groups of lines (multiplets) with relative intensities in the ratio 3 : 2. Other compound of the same formula exhibited two lines with relative area of 9 : 1. What are these compounds.

A Diethyl ether and n-butanol

B t-Butyl alcohol and 1-Methoxypropane

C diethyl ether and t-Butyl alcohol

D Diethyl ether and 2-Methoxypropane

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