A chemist used thin-layer chromatography (TLC) to analyze a mixture of amino acids obtained from a hydrolyzed protein sample.
The resulting chromatogram is shown below:
a.[2]
The Rf R_f\,Rf value of the amino acid spot was determined to be 0.56. Calculate the distance moved by the solvent front, in cm\text{cm}cm, if the amino acid spot traveled 7.0 cm from the start line. Show your working.
b.[1]
Explain why the Rf R_f\,Rf value of the amino acid remains unchanged even if the solvent front is allowed to travel a longer distance up the chromatogram plate.