Question

For $\alpha$-amino acids having the structure $R-\underset{N{H}_2}{\underset{|}{C}H}-COOH$

Which of the following statements are true?

A. Water solubility is maximum at a pH when concentrations of anions and cations are equal
B. They give ninhydrin test
C. On reacting with nitrous acid they give off $N_2$

• A. All
• B. B and C
• C. A and B
• D. only A

Answer 1

The correct option is B B and C

Option (b)

The pH at which the concentration of cations is equal to the concentration of anions is called the isoelectric point (pI).
At the pI value, an amino acid may exist as an "internal salt" and thus the pI value typically corresponds to that pH at which the particular amino acid is least water soluble.