Chapter 4 Multiple Choice Questions

. Which one of the following nuclei has a magnetic moment (so that an NMR experiment can be performed)?

. In a proton NMR experiment with a frequency (v) of 60 MHz, the magnetic field B required for resonance is 1.4 T. Calculate the magnetic field required for resonance of the proton in a spectrometer with a frequency of 500 MHz.

. The ratio of the magnetic moments (μ) for 1H and 13C is 4:1. If the frequency for a given 1H NMR spectrometer is 400 MHz what is the appropriate frequency for 13C (given that the magnetic field remains the same)?

. Which of the following is the order of the chemical shifts (in units of ppm, δ) for the OH (1), CH2 (2) and CH3 (3) protons in ethanol?

. Which of the following is the order of chemical shift (in units of δ) for the molecules CHCl3, CH2Cl2 and CH3Cl?

. For the following four molecules: acetone, benzene, dimethyl ether, ethane (each of which contains only one type of proton) the correct order of chemical shift (in δ units) is which of the following?

. In the proton and carbon (decoupled) NMR spectra recorded in experiments for p-xylene (1,4,-dimethylbenzene), the number of resonances observed in each case will be which of the following?

. How many peaks will be seen in the alkene region (δ ca. 5) of the 1H NMR spectrum of the molecule Cl-CH=CH-CO2H?

. The molecule shown in question 8 is believed to be the trans isomer. Which of the following approximate splittings (J) would you expect to be observed?

. In a 31P NMR experiment on an unknown compound, a single resonance with a septet pattern (1:6:15:20:15:6:1) is observed. Which of the following structures would be consistent with this observation?

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