In organic chemistry, the relationship between enantiomers and chiral molecules is that enantiomers are a pair of chiral molecules that are non-superimposable mirror images of each other. Chiral molecules are molecules that have a central carbon atom called a chiral center bonded to four different groups, making them asymmetric. Due to this asymmetry, chiral molecules exist in two different forms, which are enantiomers.An example of a chiral molecule is 2-butanol C4H10O . The chiral center in 2-butanol is the second carbon atom, which is bonded to four different groups: a hydrogen atom, a hydroxyl group OH , a methyl group CH3 , and an ethyl group C2H5 . The two enantiomers of 2-butanol are R -2-butanol and S -2-butanol.Enantiomers have identical physical properties, such as boiling points, melting points, and solubilities. However, they differ in their interaction with plane-polarized light. One enantiomer will rotate plane-polarized light in a clockwise direction dextrorotatory, denoted as + or d- , while the other enantiomer will rotate it in a counterclockwise direction levorotatory, denoted as - or l- . This property is called optical activity.In terms of chemical properties, enantiomers have the same reactivity with achiral reagents but differ in their reactivity with other chiral molecules. This difference in reactivity is particularly important in biological systems, as many biomolecules are chiral and can selectively interact with one enantiomer over the other. This selective interaction can lead to different biological activities or effects for each enantiomer. For example, the S -enantiomer of the drug ibuprofen is responsible for its anti-inflammatory and analgesic effects, while the R -enantiomer is less active.