Nuclear Magnetic Resonance Spectroscopy

Question 1

what is spin-spin coupling? (1)

Answer 1

NMR peaks they are split into particular patterns

Question 2

why does spin-spin coupling occur? (10

Answer 2

it happens because the applied magnetic field felt by any hydrogen atom is affected by the magnetic field of the hydrogen atoms on the neighbouring carbon atoms.

Question 3

what is the function of of spin-spin splitting? (1)

Answer 3

it gives information about the neighbouring hydrogen atoms, which can be helpful when working out structure.

Question 4

What is the n + 1 rule? (1)

Answer 4

n hydrogens on an adjacent carbon atom will split a peak into n+1 smaller peaks.

Question 5

how are NMR normally run? (1)

Answer 5

they are normally run in solution, the solvent must not contain any hydrogen atoms, otherwise the signal from the hydrogen atoms in the solution would swamp the signals from the hydrogen atoms in the sample because there are vastly more of them.

Question 6

what is a commonly used solvent? (1)

Answer 6

tetrachloromethane other solvents contain deuterium which does not produce the same NMR signal as hydrogen.