Question

Assertion: All naturally occurring $\alpha$-amino acids except glycine are optically active.

Reason: Most naturally occurring amino acids have 𝐿-configuration.

• A. Assertion and reason both are correct statements and reason explains the assertion.
  
• B. Assertion is wrong statement and reason is correct statement.
  
• C. Assertion is a correct statement and reason is a wrong statement.
  
• D. Both assertion and reason are wrong statements.
  
• E. Assertion and reason both are correct statements but reason does not explain assertion

Answer 1

The correct option is E Assertion and reason both are correct statements but reason does not explain assertion

Assertion

Except glycine, all other naturally occurring $\alpha$-amino acids are optically active. This is because glycine does not have a chiral carbon centre (due to its plane of symmetry).

For a molecule to be chiral, one carbon atom must have four different groups attached to it or it should not have a plane of symmetry & centre of symmetry.

Glycine has only three different groups on it.

So, the assertion is a correct statement.

Reason

Most naturally occurring amino acids have
$L$−configuration. The relative configuration “$L$” is taken from the reference molecule Glyceraldehyde.
So, reason is also correct but does not explain the assertion.

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