NMR introduction

full form of NMR spectroscopy s

• Nuclear Magnetic Resonance

• Nil Magnetic Resonance

• Nuclear Magnet Resonance

• Nuclear Magnetic Re

Which of the compound is taken as standard for recording chemical shift?

• Dimethylsilane

• Trimethylsilane

• Tetramethylsilane

• Methylsilane

NMR can only be done with 

• molecules
• ¹H and ¹³C
• any element with a odd number of protons
• any element with a odd number of nucleons

What does the chemical shift represent?

• resonant frequency of a specific nucleus (C or H environment)

• Frequency of vibrations of electrons

• The shielding of a magnetic field

• the number of environments

Why do we use deuterated solvents in NMR?

• Because deuterium is neutral

• Because deuterium doesn't produce any signal

• Because deuterium has an even number of protons and doesn't produce a detectable resonance

• Because deuterium has an even number of nucleons and doesn't produce a detectable resonance

Do peaks located upfield represent atoms (C or H) more or less shielded?

• MORE

• LESS

• I AM LOST

• I GIVE UP

Why do I know that downfield peaks represent C or H environments located next to pi bonds or electronegative elements?

• Because pi bonds or electronegative elements are de-shielding the environment (which needsl essenergy (frequency) to resonate.

• Because pi bonds or electronegative elements are shielding the environment (which needs less energy (frequency) to resonate.

• Because pi bonds or electronegative elements are de-shielding the environment (which needs more energy (frequency) to resonate.

• Because pi bonds or electronegative elements are shielding the environment (which needs more energy (frequency) to resonate.

What is a chemical environment in NMR?

• A C or H that have the same isotopes.

• A C or H that have the same bond sequence around them.

• Any atom that are bonded to same groups

• Any molecule that has same number of atoms

What is the "nuclear spin"?

• Different energy of the electrons given by the type of spin

• Different energy of the neutrons given by the type of spin

• Different energy of the protons given by the type of spin

• Different energy of the nucleons given by the type of spin

Which type of electromagnetic waves are used in NMR experiments?

• Infrared waves

• Microwaves

• Radio waves

• Ultraviolet waves