Ans. Structural Isomerism: Compounds having the same molecular formula but different structure i.e. different arrangement of atoms within the molecule are called structural isomers and the phenomenon is called as structural isomerism.
Types:
• Chain isomerism
• Position isomerism
• Functional isomerism
• Metamerism
• Tautomerism
Stereoisomerism: Isomers which have the same structural formula but have different relative arrangement of atoms or groups in space are called stereo isomers and the phenomenon is called as stereoisomerism.