Question

In aqueous solution, amino acids mostly exist as:

• A. $H_{2}N-CH\left(R\right)-COOH$
• B. $H_{2}N-CH\left(R\right)-CO{O}^{-}$
• C. $H_3{N}^{+}-CH\left(R\right)-COOH$
• D. $H_3{N}^{+}-CH\left(R\right)-CO{O}^{-}$

Answer 1

The correct option is D $H_3{N}^{+}-CH\left(R\right)-CO{O}^{-}$

In aqueous solution, amino acids mostly exist as Zwitter ions. Amino group is protonated and carboxylic group is deprotonated.