Assertion: Stereoisomers which are not mirror image of each other are called diastereomers.
Reason: Disasteromers may or may not be optically acitve.

The stereoisomers which are superimposable mirror images of each other are called enantiomers.

Optical isomers which are non-superimpo sable mirror images of each other are called

Optical isomers, which are non-super imposable images of each other are called

Structural isomers have different covalent linkage of atoms. Stereoisomers are compounds that have same sequence of covalent bonds but differ in the relative dispositions of their atoms in space. Geometri cal and optical isomers are the two important types of configurational isomers. The compound with double bonds or ring structure have restricted rotation, so exist in two geometrical forms. The double bonds in larger rings (ring size 10 carbon large) can also cause geometrical isomerism. The optical isomers rotate the plane of plane-polarised light. A sp^(3) -hybridised carbon atom bearing four different types of substituents is called an asymmetric centre or chiral centre. A chiral object or molecule cannot be superimposed on its mirror image. Stereoisomers that are mirror images of each other are called enantiomers. The stereosomers that the pot mirror images of each other are called diastereomers. Diasteremers have different physical properties. A racemic mixture is optically inactive and contains equal amounts of both the enantiomers. Resolution refers to method of separating a racemic mixture. Into two pure enantiomers. A meso compound is an optically inactive stereoisomer, which is achiral due to the presence of an internal plane of symmetry or centre of symmetry within the molecule. The number of chiral centres present in the following compounds is

Structural isomers have different covalent linkage of atoms. Stereoisomers are compounds that have same sequence of covalent bonds but differ in the relative dispositions of their atoms in space. Geometri cal and optical isomers are the two important types of configurational isomers. The compound with double bonds or ring structure have restricted rotation, so exist in two geometrical forms. The double bonds in larger rings (ring size 10 carbon large) can also cause geometrical isomerism. The optical isomers rotate the plane of plane-polarised light. A sp^(3) -hybridised carbon atom bearing four different types of substituents is called an asymmetric centre or chiral centre. A chiral object or molecule cannot be superimposed on its mirror image. Stereoisomers that are mirror images of each other are called enantiomers. The stereosomers that the pot mirror images of each other are called diastereomers. Diasteremers have different physical properties. A racemic mixture is optically inactive and contains equal amounts of both the enantiomers. Resolution refers to method of separating a racemic mixture. Into two pure enantiomers. A meso compound is an optically inactive stereoisomer, which is achiral due to the presence of an internal plane of symmetry or centre of symmetry within the molecule. The following two compounds are