Chirality
A molecule is called CHIRAL if it is optically active.Chirality also refers to enantiomerism. A molecule or species is optically active if the mirror image of it is nonsuperimposable on it.
Example 1 :
R-2-Chlorobutane : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration S-2-Chlorobutane and it is non superimposable on it.
Example 2 :
S-2-Chlorobutane : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration R-2-Chlorobutane and it is non superimposable on it.
Example 3 :
R-2-Butanol : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration S-2-Butanol and it is non superimposable on it.
Example 4 :
S-2-Butanol : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration R-2-Butanol and it is non superimposable on it.
Example 5 :
R-Lacticacid : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration S-Lacticacid and it is non superimposable on it.
Example 6 :
S-Lacticacid : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration R-Lacticacid and it is non superimposable on it.
Example 7 :
R,R-Tartaricacid : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration S,S-Tartaricacid and it is non superimposable on it.
Example 8 :
S,S-Tartaricacid : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration R,R-tartaricacid and it is non superimposable on it.
Example 9 :
R,S-Tartaricacid : It is achiral.It has plane as well as center of symmetry.It is optically inactive .The mirror image of the molecule has identical configuration and it is superimposable on it. It is also known as meso Tartaric acid. It is optically inactive due to INTERNAL COMPENSATION.
Example 10 :
R,R-Dichlorocyclopropane : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration S,S-Dichlorocyclopropane and it is non superimposable on it.
Example 11 :
S,S-Dichlorocyclopropane : It is chiral.It has no plane or center of symmetry.It is optically active .The mirror image of the molecule has opposite configuration R,R-Dichlorocyclopropane and it is non superimposable on it.
Example 12 :
R,S-dichlorocyclopropane : It is achiral.It has plane as well as center of symmetry.It is optically inactive .The mirror image of the molecule has identical configuration and it is superimposable on it. It is also known as meso Dichlorocyclopropane. It is optically inactive due to INTERNAL COMPENSATION.