Question

Given below are two statements. one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : A solution of the product obtained by heating a mole of glycine with a mole of chlorine in presence of red phosphorous generates chiral carbon atom.
Reason R : A molecule with 2 chiral carbons is always optically active.
In the light of the above statements, choose the correct answer from the options given below:

• A. A is true but R is false
• B. Both A and R are true but R is NOT the correct explanation of A
• C. Both A and R are true and R is the correct explanation of A
• D. A is false but R is true

Answer 1

The Correct Option is A

Assertion (A):

Glycine (\( \text{NH}_2\text{CH}_2\text{COOH} \)) reacts with chlorine (\( \text{Cl}_2 \)) in the presence of red phosphorus to undergo alpha-halogenation. The reaction produces 2-chloroacetic acid (\( \text{NH}_2\text{CHClCOOH} \)) as the product:

\[ \text{NH}_2\text{CH}_2\text{COOH} + \text{Cl}_2 \xrightarrow{\text{Red P}} \text{NH}_2\text{CHClCOOH} \]

In the product, 2-chloroacetic acid (\( \alpha \)-chloroacetic acid), the carbon marked with an asterisk is a chiral carbon:

This assertion is true.

Reason (R):

The reason states that a molecule with two chiral carbons is always optically active. This is false, as a molecule with two chiral centers can be optically inactive if it has an internal plane of symmetry. Such molecules are called meso compounds.

Final Answer:

Assertion (A) is true, but Reason (R) is false.