Provide detailed information about the relationship between optical activity and molecular structure.

(N/A) In $1874$,Dutch scientist $J. van't\,Hoff$ and French scientist $C. LeBel$ independently proposed the relationship between optical activity and molecular structure.
$(i)$ Central Carbon: In a compound,the four groups (valencies) around the central carbon atom are arranged tetrahedrally.
$(ii)$ Asymmetric Carbon: If all four substituents attached to a carbon atom in a compound are different,such a carbon is called an asymmetric carbon or stereocenter.
$(iii)$ Asymmetry and Optical Activity: Molecules containing an asymmetric carbon (stereocenter) lack symmetry and are asymmetric. Such asymmetric molecules exhibit optical activity.
$(iv)$ Chiral,Chirality,and Optical Activity: Organic molecules that cannot be superimposed on their mirror images are called chiral structures,and this property is known as chirality.
Molecules possessing chirality contain an asymmetric carbon and exhibit optical activity.
$(v)$ Enantiomers: Stereoisomers that are non-superimposable mirror images of each other are called enantiomers.
They are chiral (asymmetric) and possess chirality (asymmetry).