Question

R and S enantiomer are differ in:

• A. Rotation of PPL
• B. Solubility in achiral solvent
• C. Chemical properties
• D. Dipole moment

Answer 1

The Correct Option is A

To solve the question regarding the differences between R and S enantiomers, we need to understand the concept of chirality in chemistry. Enantiomers are a type of stereoisomer that are mirror images of each other but cannot be superimposed. They possess identical physical properties except for the direction in which they rotate plane-polarized light (PPL). This is a critical property of enantiomers and is used to differentiate between the two.

Step-by-Step Explanation:

1. Definition of Enantiomers: Enantiomers are molecules that are non-superimposable mirror images of each other. They have one or more chiral centers.
2. Rotation of Plane-Polarized Light: The most notable distinction between R and S enantiomers is their ability to rotate plane-polarized light in different directions. This property is a direct result of chirality:
   • An R-enantiomer will rotate light in one direction (either clockwise or counterclockwise).
   • An S-enantiomer will rotate light in the opposite direction but by the same magnitude.
3. Choice Analysis:
   • Rotation of PPL: This option correlates directly with the primary difference between R and S enantiomers, as explained above. Hence, this is the correct answer.
   • Solubility in Achiral Solvent, Chemical Properties, Dipole Moment: These properties are not typically different between R and S enantiomers. Enantiomers in achiral environments have identical chemical properties and solubility. Also, dipole moment is a structural parameter that does not differ between enantiomers.

Conclusion: The correct difference between R and S enantiomers lies in the direction of the rotation of plane-polarized light. Thus, the answer is Rotation of PPL.