Optical isomers

• What is optical isomerism?

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

  A chiral centre is a carbon atom bonded to four different groups, resulting in no line of symmetry.

  
• How is a chiral centre indicated in a molecular structure?

  It is commonly indicated using an asterisk (*) 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 it optically inactive.
• How do nucleophilic addition reactions lead to the formation of optical isomers?

  Nucleophiles can attack a carbonyl group from above or below the carbon-oxygen double bond, producing mirror image products.
• What is the mechanism of nucleophilic addition reactions that leads to optical isomers?

  • Nucleophiles attack a carbonyl group.
  • Attack can occur from above or below the carbon-oxygen double bond.
  • Results in two possible products that are mirror images (optical isomers).