Question

For $\alpha$ - amino acid having the structure,
$R-\underset{N{H}_2}{\underset{|}{CH}}-C{O}_{2}H$

Which of the following statements are true?
(A) Water solubility is maximum at a pH when the concentration of anions and cations are equal.
(B) They give ninhydrin test.
(C) On reacting with nitrous acid, they give of $N_2$.

• A. All
• B. B and C
• C. A and B
• D. None of these

Answer 1

The correct option is B B and C

At isoelectric point, amino acids has minimum solubility in water.
Amino acids or $\alpha$-amino acids give ninhydrin test.
With $HN{O}_2,$ $\alpha$-amino acids gives hydroxyacids and $N_2$ gas.
$R\stackrel{\stackrel{N{H}_2}{|}}{CH}COOH\stackrel{HN{O}_2}{\to }R\underset{HO}{\underset{|}{C}}HCOOH+N_2$