Questions: Chapter 21 Nuclear Species Quiz (4th Edition) 20. The NMR spectrum of hydrogen does not contain information about phosphorous because of differences in: A. spin density B. relaxation times C. nuclear mass D. Larmor frequency

Solution Steps

The question asks why the NMR spectrum of hydrogen does not contain information about phosphorus. It provides four possible reasons: spin density, relaxation times, nuclear mass, and Larmor frequency.

• Spin density: This refers to the distribution of electron spin in a molecule, which is not directly related to the NMR signal of different nuclei.
• Relaxation times: These are related to how quickly nuclei return to equilibrium after being disturbed, but they do not explain why hydrogen and phosphorus would not interact in an NMR spectrum.
• Nuclear mass: While different nuclei have different masses, this does not directly affect the NMR spectrum in terms of detecting other nuclei.
• Larmor frequency: This is the frequency at which a nucleus precesses in a magnetic field. Different nuclei have different Larmor frequencies, which means they resonate at different frequencies in an NMR spectrum.

The key reason why the NMR spectrum of hydrogen does not contain information about phosphorus is due to the difference in their Larmor frequencies. Each type of nucleus resonates at a specific frequency, and hydrogen and phosphorus have different Larmor frequencies.

Final Answer