Engineering Chemistry MCQ (Nuclear Magnetic Resonance)

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Engineering Chemistry MCQ (Nuclear Magnetic Resonance)

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1. The nuclei with a spin quantum number greater than _______ can exhibit the NMR phenomenon.
a) 0
b) 5
c) 10
d) -5
Answer: a
Explanation: The nuclei with a spin quantum number greater than zero can exhibit
the NMR phenomenon. Nuclear magnetic resonance spectroscopy, NMR
spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei.

2. The number of different orientations which a magnetic nucleus can take is ____________
a) 2I
b) 2I-1
c) 2I+1
d) 4I
Answer: c
Explanation: The number of different orientations that a magnetic nucleus can take is 2I+1.

3. Number of NMR signals obtained in CH3COCH3 will be ____________
a) 6
b) 3
c) 2
d) 1
Answer: d
Explanation: Number of NMR signals obtained in CH3COCH3 will be 1. Nuclear
magnetic resonance spectroscopy, is a research technique that exploits the
magnetic properties of certain atomic nuclei.

4. Propene as well as 2-Butene(cis) will show equal number of signals in their NMR spectra.
a) True
b) False
Answer: b
Explanation: Propene as well as 2-Butene(cis) will not show equal number of signals in their NMR spectra.

5. Select the incorrect statement from the following option.
a) TMS stands for tetra methyl silane
b) All the hydrogen in TMS have the same chemical shift
c) TMS has a high boiling point, so it is not easily lost when holding the NMR sample
d) TMS is relatively unreactive with most functional groups
Answer: c
Explanation: TMS has a low boiling point so it can be easily removed from a
recoverable sample of an organic compound. All the other options are correct. TMS
is relatively unreactive with most functional groups.

6. The NMR spectra of the functional isomers of the molecular formula C2H6O show _________ and _________ signals respectively.
a) 1, 2
b) 1, 3
c) 1, 4
d) 1, 5
Answer: b
Explanation: The NMR spectra of the functional isomers of the molecular formula C2H6O show one and three signals respectively.

7. The number of signals in 1-propanol are _________ while those in 2-propanol are ______
a) 4, 3
b) 4, 2
c) 2, 4
d) 3, 4
Answer: a
Explanation: The number of signals in 1-propanol are 4 while those in 2-propanol are 3.

8. For NMR spectrum, carbon tetrachloride and water can be successfully used as a solvent.
a) True
b) False
Answer: a
Explanation: For the NMR spectrum, carbon tetra-chloride and water can be
successfully used as a solvent. NMR is routinely used in advanced medical imaging
techniques, such as in magnetic resonance imaging (MRI).

9. In how many ways –CH3 protons can couple with the protons on adjacent carbon atom relative to the external field.
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: In four ways –CH3 protons can couple with the protons on adjacent carbon atom relative to the external field.

10. Which of the following is inversely proportional to the chemical shifts positions (δ)?
a) Frequency of unknown group of protons
b) Frequency of TMS
c) Operating frequency of the instrument
d) All of the mentioned
Answer: c
Explanation: Operating frequency of the instrument is inversely proportional to the chemical shifts positions (δ).