Q.The amino acid without chiral carbon is :

A chiral carbon must carry four different groups. In glycine, the α-carbon bears two identical H atoms, so it is not chiral.

All standard amino acids have the general structure $H_2N-CH(R)-COOH$, where the α-carbon is bonded to an $-NH_2$ group, a $-COOH$ group, an H atom, and the side chain R. For the α-carbon to be a chiral (asymmetric) centre, all four substituents attached to it must be different.

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