Organic Chemistry MCAT Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Enantiomers are stereoisomers that are non-superimposable mirror images of each other, exhibiting chirality. One of the critical characteristics of enantiomers is their interaction with plane-polarized light, which is a beam of light that vibrates in a single plane.

When plane-polarized light passes through a solution containing an enantiomer, the enantiomer will rotate the plane of polarization. Each enantiomer affects the light differently: one will rotate the light in a clockwise direction (known as dextrorotatory), while the other will rotate it in a counterclockwise direction (known as levorotatory). These rotations occur to equal extents but in opposite directions, which is why the correct answer reflects this unique property of enantiomers.

It’s important to note that the extent of rotation depends on factors including the concentration of the solution and the path length through which the light travels, but the fundamental property remains that enantiomers have equal but opposite effects on the rotation of plane-polarized light. This characteristic is utilized in determining the purity of chiral compounds and in various applications in pharmaceuticals and natural products.