Question

Which of the following statement is NOT correct about a racemic mixture?

• A. It is an equimolar mixture of enantiomers.
• B. Enantiomers have identical refractive index.
• C. It is optically active.
• D. It is optically inactive.

Hint:

A racemic mixture has equal amounts of two enantiomers whose rotations cancel, so it is optically inactive.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
A racemic mixture contains equal amounts of the d- and l-enantiomers.

Step 2: Check the statements
(A) Correct: it is an equimolar mixture of enantiomers.
(B) Correct: enantiomers have the same physical properties such as refractive index.
(D) Correct: the equal and opposite rotations cancel, so the mixture is optically inactive.

Step 3: Find the wrong one
Statement (C), that a racemic mixture is optically active, contradicts statement (D). It is the incorrect one.

Final Answer:
The incorrect statement is that a racemic mixture is optically active. \[ \boxed{\text{(C) }\text{It is optically active.}} \]