Ncert Exercises & Solutions

Given below are two statements:

Assertion (A):	All naturally occurring α -amino acids except glycine are optically active.
Reason (R):	Most naturally occurring amino acids have L-configuration.

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	(A) is false but (R) is true.

Hint: Glycine is optically inactive because it does not contain a chiral center.

All naturally occur

α

-amino acids except glycine are optically active. Glycine is optically inactive because glycine does not

have all four different substituents as shown below.

Most naturally occurring amino acids have a $L -$ configuration. $L -$ amino acids are represented by writing the $- N H_{2}$ group on

the left-hand side.

Hence, Assertion and reason both are correct statements but reason does not explain assertion.