Question

What will be the behaviour of the compound having molecular formula $N{H_2} - C{H_2} - COOH$ ?

Answer 1

Hint: $N{H_2} - C{H_2} - COOH$ molecule has three groups, namely an amino group, an alkyl group, and a carboxylic acid group. The amino group usually carries positive charge, while the carboxylic acid group carries negative charge. While taking this into account, we can propose the behaviour of the molecule.

Complete answer:
$N{H_2} - C{H_2} - COOH$ is Glycine. It is an amino acid. Amino acids are organic molecules which are essentially the building blocks of protein molecules. They have the general molecular formula $N{H_2} - R - COOH,$ where R is any alkyl group. They usually consist of an acidic $ - N{H_2}$ group, which is an amino group, and a basic $ - COOH$ group, which is a carboxylic acid group, bonded to the same carbon atom.
Since $N{H_2} - C{H_2} - COOH$ has both acidic and basic groups, it exhibits amphoteric properties. This means that in an acidic medium, the molecule is positively charged and behaves as a base (proton acceptor) and in the basic medium, the molecule is negatively charged and behaves as an acid (proton donor).
In solution, $N{H_2} - C{H_2} - COOH$ exists as zwitterions. Zwitterions are those ions which have both positive and negative charge in the same molecule. It does not have an aggregate charge, but includes differently charged positive and negative parts in the molecule.

Note:
At physiologic pH, amino acids are usually ionized. The pH at which amino acids have neutral charge is known as isoelectric point. At pH lower than isoelectric point, they have positive charge, while at pH higher than isoelectric point, they have negative charge.