Question

Define mesomers with an example.

Answer 1

Mesomers:

• Mesomers are the type of organic compounds in which two chiral carbons are present and those two are similar.
• A meso compound is a kind of stereoisomer that has two or more chiral centres but is optically inactive because it has an internal plane of symmetry.
• In these types of compounds, the net rotation of plane polarised light is zero.
• For example, 2,4 pentanediol.
• 

Stereoisomer

• Stereoisomers are molecules that have the same molecular formula and differ only in how their atoms are arranged in three-dimensional space and the stereoisomer category has several further subcategories. Two main types of stereoisomers are geometrical isomers and optical isomers.
• Optical isomers are molecules whose structures are mirror images that cannot be superimposed on one another in any orientation. Those molecules are called chiral they do not possess the plane of symmetry.
• 2,4 pentanediol comes under optical isomerism.

Isomerism

• Isomerism is the phenomenon in which more than one compounds have the same chemical formula but different chemical structures.
• here are two primary types of isomerism, which can be further categorized into different subtypes. These primary types are Structural Isomerism and Stereoisomerism.