Analytical chemistry

Question 1

Explain the use of CDCl3 as the solvent when obtaining these spectra in proton NMR

Answer 1

CDCl3 does not cause a peak and does not interfere with spectrum/peaks

Question 2

Which functional groups react with D2O

Answer 2

OH
COOH
NH2

Question 3

What is meant by Rf value

Answer 3

Distance travelled by amino acid divided by distance travelled by solvent.

Question 4

The spectrum obtained when the solvent D2O is used with the substance COOH, OH and NH2 is different. Describe this difference and explain your answer (1)

Answer 4

COOH/NH2/OH peak disappears as proton/hydrogen exchanges with deutrium/D

Question 5

Suggest an explanation for a molecule to have a larger Rf value than another.

Answer 5

Molecules is more soluble in the solvent used.

Question 6

Suggest an explanation for a molecule to have a smaller Rf value than another

Answer 6

Molecule is more attracted to the stationary phase used.