JEE Main Chemistry question

At intermediate pH values of about 6.0, an amino acid behaves as a dipolar ion or Zwitter ion. On decreasing and increasing the pH values, the amino acid becomes

(A)Basic and acidic respectively
(B)Acidic and basic respectivelyCorrect
(C)Remains in the state of a neutral molecule
(D)Loses its optical activity with the exception of glycine

Answer: (B)

Solution

Lowering the pH below the isoelectric point protonates the carboxylate group, converting the amino acid into its cationic form, which behaves as an acid (it can donate a proton); raising the pH above the isoelectric point deprotonates the ammonium group, converting the amino acid

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Question ID VK-150791