मराठी

Optical Isomerism in Halogen Derivatives

Advertisements

Topics

Estimated time: 4 minutes
Maharashtra State Board: Class 12

Key Points: Optical Isomerism in Halogen Derivatives

  • Optical activity: Ability of a compound to rotate plane-polarised light
  • Dextrorotatory (+): rotates light to the right
  • Laevorotatory (–): rotates light to the left
  • (+) and (–) forms are called optical isomers, and the phenomenon is optical isomerism
  • Number of optical isomers = 2ⁿ
    (n = number of asymmetric carbon atoms)
  • Asymmetric carbon/stereocentre: Carbon attached to four different groups
  • Chirality: Property of a molecule whose mirror image is non-superimposable
  • Enantiomers: Stereoisomers which are non-superimposable mirror images of each other
  • Retention: Preservation of spatial arrangement around the asymmetric carbon during reaction
  • Inversion of configuration: In the SN2 reaction, backside attack gives a product with the opposite configuration. This complete inversion is called Walden inversion
  • Racemic mixture: Equimolar mixture of dextro and laevo isomers. It is optically inactive due to external compensation. This phenomenon is called racemisation.

Representation of configuration:

Fischer projection:

  • Horizontal bonds → above plane
  • Vertical bonds → below plane

Wedge formula:

  • Solid wedge → above plane
  • Dashed wedge → below plane
  • Straight line → in plane
Advertisements
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×