15. Analytical Techniques:IR, NMR, Mass Spect

(a) Calculate the resonance frequency of an aldehydic proton ( δ 9.3 ppm) if it is detected on a 60-MHz NMR spectrometer.

(b) What if it were detected on a 300-MHz instrument?

In ${13}^C$ NMR spectroscopy, which of the following is the most likely chemical shift range (in ppm) for a carbonyl carbon ($C=O$) in an aldehyde or ketone?

In ${13}^C$ NMR spectroscopy, how many distinct carbon signals would be observed for the compound ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$ (n-butane)?

Answer the following questions:

c. What is the relationship between coupling constant in hertz and operating frequency?

d. How does the operating frequency in NMR spectroscopy compare with the operating frequency in IR and UV/Vis spectroscopy?

If two signals differ by 90 Hz in a 300 MHz spectrometer, by how much do they differ in a 500 MHz spectrometer

(A true story.) A major university was designated as a national nuclear magnetic resonance center by the National Science Foundation. Several large superconducting instruments were being installed when a government safety inspector appeared and demanded to know what provisions were being made to handle the nuclear waste produced by these instruments. Assume you are the manager of the NMR center, and offer an explanation that could be understood by a nonscientist.