Using the chromatogram together with the $R_f$ values, deduce which amino acid gives spot A and which gives spot B.
A second chromatogram of the same mixture is run with a more polar solvent. Predict how the $R_f$ values of the amino acids change, and explain why.
Complete the equations to illustrate the acid-base behaviour of glycine, $\text{H}_2\text{NCH}_2\text{CO}_2\text{H}$.\n\n$\text{H}_2\text{NCH}_2\text{CO}_2\text{H}$(aq) $+$ $\text{HCl}$(aq) $\rightarrow$ \n\n$\text{H}_2\text{NCH}_2\text{CO}_2\text{H}$(aq) $+$ $\text{NaOH}$(aq) $\rightarrow$
In aqueous solution, amino acids are present as zwitterions. Draw the zwitterionic structure of glycine and explain how glycine’s zwitterion is formed.
Except for glycine, every naturally occurring amino acid has a chiral centre and shows stereoisomerism. Draw the two stereoisomers of alanine, $\text{CH}_3\text{CH(NH}_2\text{)CO}_2\text{H}$.
Alanine can be prepared from 2-chloropropanoic acid, $\text{CH}_3\text{CHClCO}_2\text{H}$. State the reagents and conditions, and name the mechanism for this reaction.
State and explain the order of acidity for trichloroethanoic acid, chloroethanoic acid and ethanoic acid.
Serine, $\text{HOCH}_2\text{CH(NH}_2\text{)CO}_2\text{H}$, may react with alanine, $\text{CH}_3\text{CH(NH}_2\text{)CO}_2\text{H}$, to give three different structural isomers, each with molecular formula $\text{C}_6\text{H}_{12}\text{N}_2\text{O}_4$. Draw the structures of these three structural isomers.