For `alpha` -amino acids having the structure `R-underset(NH_(2))underset(|)(C)H-CO_(2)H`
Which of the following statements are true
(A) Water solubility is maximum at a pH when concentration of anion and cation are equal
(B)They give ninhydrin test
(C) On reacting with nitrous acid give off `N_(2)`

Options

A. All
B. B and C
C. A and B
D. A

Answer

B

Explanation

Ninhydrin test is useful for qualitative determination of amines and `alpha` - amino acids. `alpha` - amino acids react with ninhydrin to give a blue-purple product. It also gives off `N_2` upon reacting with nitrous acid.
`H_3C -underset(""^+NH_3)underset(|)CH-COO^(-) + HONO to H_3 C - underset(OH)underset(|)CH-COOH + N_2 uarr + H_2 O`
Hence (B) and (C) both are correct.