Chirality in chemistry refers to the property of a molecule that makes it non-superimposable on its mirror image, much like your left and right hands. These mirror-image molecules are called enantiomers.

Chiral molecules typically have a carbon atom bonded to four different groups, known as a chiral center or stereocenter. Because of their unique spatial arrangement, enantiomers have identical physical and chemical properties in most environments—but they differ in an important way: their optical activity.

Optical activity refers to a molecule’s ability to rotate plane-polarized light:

• One enantiomer will rotate light to the right (dextrorotatory, +)
• The other will rotate it to the left (levorotatory, –)

This property is crucial in fields like pharmaceuticals, where one enantiomer of a drug might be therapeutic, while the other could be ineffective or harmful. Chirality also plays a vital role in biochemistry, as many biological molecules (like amino acids and sugars) are chiral and often only one form is biologically active.

Thus, chirality directly influences molecular behavior, biological function, and optical properties.