(i) Racemic mixture : Equal portions of Enantiomers combined to form an optically inactive mixture. This mixture is called racemic mixture.
(1) Here rotation due to one isomer will be exactly cancelled by the rotation of due to other isomer.
(2) The process of conversion of enantiomer into a racemic mixture is called as racemisation.
(ii) Retention of configuration : The preservation of integrity of the spatial arrangement of bonds to an asymmetric centre during a chemical reaction (or) transformation is called Retention of configuration.
General Eg : Conversion of XCabc chemical species into YCabc.
Eg : (–) 2 – Methyl 1 – butanol conversion into (+) 1 – chloro 2. Methyl butane
Enantiomers : The stereo isomers related to each other as non-superimposable mirror images are called enantiomers.
→ These have identical physical properties like melting point, boiling points refractive index etc.
→ They differ in rotation of plane polarised light.
