NMR Concepts and Applications

Which type of nuclei is suitable for NMR spectroscopy?

• Nuclei with no protons or neutrons

• Nuclei with an odd number of protons or neutrons

• Nuclei with an even number of protons and neutrons

• Nuclei with an even number of protons or neutrons

Why is Carbon-13 suitable for NMR spectroscopy while Carbon-12 is not?

• Carbon-13 has an even number of protons

• Carbon-12 has an odd number of neutrons

• Carbon-13 has an odd number of neutrons

• Carbon-12 has an odd number of protons

What is the most common form of hydrogen used in proton NMR?

• Hydrogen with one proton and no neutrons

• Deuterium

• Tritium

• Hydrogen with one neutron

What happens to the magnetic fields of protons in an applied magnetic field?

• They align randomly

• They align with or against the external field

• They lose their magnetic properties

• They become neutral

What is the alpha spin state?

• A state with no energy difference

• A state with higher energy

• A state aligned against the magnetic field

• A state aligned with the magnetic field

What type of energy is required to flip a hydrogen nucleus from the alpha to the beta spin state?

• Thermal energy

• Radio frequency energy

• Kinetic energy

• Potential energy

What does the gyromagnetic ratio represent?

• The energy difference between spin states

• The property of the nucleus related to its magnetic moment

• The strength of the magnetic field

• The ratio of protons to neutrons

How is the frequency needed for NMR calculated?

• By adding the gyromagnetic ratio to the magnetic field strength

• By dividing the gyromagnetic ratio by the magnetic field strength

• By multiplying the gyromagnetic ratio by the magnetic field strength

• By dividing the gyromagnetic ratio by 2π and multiplying by the magnetic field strength

What is the gyromagnetic ratio for a hydrogen nucleus?

• 6.688 x 10^7

• 2.675 x 10^8

• 3.675 x 10^7

• 1.675 x 10^8

What is the operating frequency of an H NMR spectrometer with a magnetic field of 11.744 Tesla?

• 700 MHz

• 400 MHz

• 600 MHz

• 500 MHz