Question

An amino acid reacts with 10 ml 0.05 M $NaOH$ and the final solution has $pH=2.30$. When 20 ml of the same base is added to the resulting solution, the $pH$ becomes 9.7. Identify the amino acid and calculate the isoelectric point of the amino acid. This amino acid is prepared by the reaction of compound $\left(X\right)$ with ${NH}_3$, and further hydrolysis with $HCN$. Compound $\left(X\right)$ is less $C$ atom-containing compound that gives positive iodoform test and positive Fehling's solution test. An amino acid is:

• A. leucine
• B. serine
• C. glycine
• D. alanine

Answer 1

The correct option is D alanine

As the given compound 'X' gives positive idoform test, therefore it should contain $C{H}_3-CO-H$ group.

Therefore amino acid is Alanine.

Isoelectric point $\left(PI\right)=\frac{p{k}_1+p{k}_2}{2}=6$