Question

How do you know if a Stereoisomer is Optically Active?

Answer 1

1. A light-rotating chiral molecule is said to be optically active. If the molecule rotates in the clockwise direction of plane-polarized light, we call the rotation a dextrorotatory rotation. If it rotates counterclockwise, we call it levorotatory rotation.
2. For$2,3-\mathrm{diol}$, the number of optically active stereoisomers available is$2$. They are optically active isomers of $\mathrm{d},\mathrm{I}$.
3. Chiral molecules are normally optically active, and similar and opposite light rotation can be demonstrated by two enantiomers.
4. Enantiomers are also often called optical isomers. A $50:50$ mixture of all enantiomers is referred to as a racemate or racemic mixture, and the light plane does not rotate.