Chemistry

2. Chiral Molecules: a) Attached with four different groups
The difference between chiral and achiral molecules can be explained on the basis of the plane of symmetry. If all
the attached group to the central carbon atom are different then there is no plane of symmetry. Such a molecule is
known as a chiral molecule.
If all the group attached to the central carbon atom are not different then there exist plane of symmetry. Such
molecules are called achiral molecules. It is clear that only molecule having chiral centre will show optical
isomerism.

4. Optical activity is the ability of a chiral molecule to rotate the plane of plane-polairsed light, measured using a
polarimeter.
Optical Isomers:
Optical isomers are two compounds which contain the same number and kinds of atoms, and bonds (i.e., the connectivity
between atoms is the same), and different spatial arrangements of the atoms, but which have non-superimposable mirror
images. Each non-superimposable mirror image structure is called an enantiomer.

5. Generally defined, stereoisomers are isomers that have the same composition but that differ in the orientation of
those parts in space. There are two kinds of stereoisomers: enantiomers and diastereomers

6. Enantiomers are chiral molecules that are mirror images of one another. Furthermore, the molecules are non-
superimposable on one another. This means that the molecules cannot be placed on top of one another and give
the same molecule. Chiral molecules with one or more stereocenters can be enantiomers

8. Diastereomers are stereoisomers that are not mirror images of one another and are non-superimposable on one
another.
Stereoisomers with two or more stereocenters can be diastereomers.
It is sometimes difficult to determine whether or not two molecules are diastereomers