Question

IUPAC name of glycine is:
A. 2-Aminopropanoic acid
B. 2-aminobutanoic acid
C. 2-aminoethanoic acid
D. 2-aminopent-1,5-dioic acid

Answer 1

The glycine is the amino acid with chemical formula $N{H_2} - C{H_2} - COOH$ where the longest chain contains two carbon atoms. The hydrocarbon which contains two carbon atoms is ethane.

Complete step by step answer:
Glycine is one of the amino acids that contains a single hydrogen atom on its side chain. The glycine is considered as the simplest amino acid. The chemical formula of the glycine is $N{H_2} - C{H_2} - COOH$.
The structure of glycine is shown below.

The IUPAC name of the chemical compound is the standard name assigned to a particular compound on the basis of some rules. The IUPAC is an abbreviation used for International union of pure and applied chemistry.
In the given structure, the parent chain contains two carbon atoms so the hydrocarbon chain is the ethane. The numbering of the chain starts from the highest priority group. In the second position of the chain one amino group ($- N{H_2}$) is attached The parent chain is the longest in the structure containing the maximum number of carbon atoms. In the first position of the chain carboxylic acid(COOH) is present so the suffix will be given as –oic. So, the resulting IUPAC name of glycine is 2-aminoethanoic acid.
Therefore, the correct option is C.

Note:
Don’t get confused while numbering the chain, as both the amino group and carboxylic acid are the functional group but carboxylic acid is highly prioritized as the molecular mass of the carboxylic group is greater than the amino group. When the functional group contains a carbon atom then it is also counted in the hydrocarbon chain.