Question

Explain the amphoteric behavior of amino acids.

Answer 1

Hint: Acids: Those compounds which on ionization produce \[{H^ + }\] ions, are known as acids.
Bases: Those compounds which on ionization produce $O{H^ - }$ ions, are known as bases.
Amphoteric Compounds: Those compounds which can react with both acids and bases are known as amphoteric compounds.

Complete step by step answer:
First of all we will discuss acids, bases, amino acids and amphoteric compounds. And also we will read some of their characteristics.
Acids: Those compounds which on ionization produce \[{H^ + }\] ions, are known as acids. They are sour in taste. Acids change the color of litmus from blue to red. When they react with bases then they become less acidic.
Bases: Those compounds which on ionization produce $O{H^ - }$ ions, are known as bases. They are slippery in nature. Bases change the color of litmus from red to blue. When they react with acids then they become less basic.
Amphoteric Compounds: Those compounds which can react with both acids and bases are known as amphoteric compounds.
Amino acids: Amino acids are a basic unit of proteins. And we know that proteins are building blocks of life. As proteins are made up of amino acids hence if we break down proteins then we will get amino acids. Amino acids are the compounds that contain amine $( - N{H_2})$ and carboxyl group $( - COOH)$ in the side chain of alkyl group $R$. By adding carboxyl group and amine group at different positions we will get different types of amino acids. Amino acids are further divided into three categories based on the number of carboxyl and amine groups present in the compound. The three categories are as: Acidic amino acids, Basic amino acids and neutral amino acids.
Acidic amino acids: Those amino acids in which the number of carboxyl groups is greater than the number of amine groups are known as acidic amino acids.
Basic amino acids: Those amino acids in which the number of carboxyl groups is less than the number of amine groups are known as basic amino acids.
Neutral amino acids: Those amino acids in which the number of carboxyl groups and the amine group are the same are known as neutral amino acids.
Hence the amino acids show the property of amphoteric compounds because of the presence of both acidic and basic groups i.e. carboxyl and amine group respectively.

Note:
Amphoteric (amphiprotic): A molecule that is both an acid and a base. Amino acids such as glycine are amphoteric. The amino group is a base (it can accept a proton). The carboxylic acid group is an acid (it can donate a proton).