MHT CET 202624 AprilMorning Shift
- Exam
- MHT CET
- Year
- 2026
- Date
- 24 April
- Shift
- Morning Shift
- Subject
- Chemistry
- Chapter
- General Organic Chemistry
MHT CET 2026 · 24 April · Morning Shift · Chemistry · General Organic Chemistry
Which of the following statement is NOT correct about a racemic...
Which of the following statement is NOT correct about a racemic mixture?
Options
- AIt is an equimolar mixture of enantiomers.
- BEnantiomers have identical refractive index.
- CIt is optically active.
- DIt is optically inactive.
Correct answer
C. It is optically active.
Step-by-step solution
A racemic mixture is an equimolar mixture of two enantiomers (dextrorotatory and levorotatory).
Because the two enantiomers rotate plane-polarized light in opposite directions by equal amounts, their rotations cancel each other out. This phenomenon is known as external compensation.
As a result, a racemic mixture has a net optical rotation of zero, making it optically inactive.
Enantiomers have identical physical properties, such as melting point, boiling point, and refractive index, differing only in their interaction with plane-polarized light and chiral reagents.
Therefore, the statement that a racemic mixture is optically active is incorrect.
Answer: It is optically active.
Because the two enantiomers rotate plane-polarized light in opposite directions by equal amounts, their rotations cancel each other out. This phenomenon is known as external compensation.
As a result, a racemic mixture has a net optical rotation of zero, making it optically inactive.
Enantiomers have identical physical properties, such as melting point, boiling point, and refractive index, differing only in their interaction with plane-polarized light and chiral reagents.
Therefore, the statement that a racemic mixture is optically active is incorrect.
Answer: It is optically active.