optical isomers

• What is optical isomerism?


  It is a type of stereoisomerism where molecules have the same molecular formula but different spatial arrangements of atoms.
• What is a chiral centre?


  A chiral centre is a carbon atom with four different groups bonded around it, resulting in no line of symmetry in the molecule.
• How is a chiral centre indicated in a molecule?


  The chiral centre is commonly indicated using * next to the asymmetric carbon.
• What are optical isomers?


  Optical isomers are two possible isomers that are mirror images of each other due to the presence of a chiral centre.
• What are the two different isomers formed from a chiral centre called?


  They are called enantiomers.
• How do enantiomers affect plane polarised light?


  Each enantiomer causes the rotation of plane polarised light by 90° in opposite directions.
• What is a racemate?


  A racemate is formed when optical isomers are produced as a pair of enantiomers in a 1:1 ratio.
• What is the overall optical effect of a racemic mixture on polarised light?


  The overall effect is zero as the opposite directions of rotation cancel out, making the mixture optically inactive.
• What type of reaction leads to the formation of optical isomers?


  Optical isomers are formed due to a nucleophilic addition reaction.
• In nucleophilic addition reactions, how do nucleophiles attack the carbonyl group?


  Nucleophiles can attack the carbonyl group from above or below the carbon-oxygen double bond.
• What is the result of nucleophilic addition reactions in terms of products?


  The two possible products of the reaction are mirror images and therefore optical isomers.
• What are the key characteristics of optical isomers and enantiomers?


  • Optical isomers have the same molecular formula but different spatial arrangements.
  • Enantiomers are a pair of optical isomers that are mirror images.
  • Each enantiomer rotates plane polarised light in opposite directions.
• What is the significance of racemic mixtures in chemistry?


  • Formed from a 1:1 ratio of enantiomers.
  • Overall optical effect is zero, making them optically inactive.
  • Important in pharmaceuticals where specific enantiomers may have different biological effects.