Explain the terms — 'Isomers' and 'Isomerism'. State the 'Characteristics of isomers' with reference to —

1. Properties of isomers
2. Number of isomers with relation to carbon atoms in the isomer.

Differentiate between — 'Chain isomerism' and 'Position isomerism ' — with suitable examples.

Isomers & Isomerism — Organic compounds having the same molecular formula but differing in molecular arrangement or in structural formula are called Isomers and the phenomenon is called Isomerism.

Characteristics of Isomers:

1. Properties of Isomers — Isomers of the same homologous series have similar chemical properties but differ in physical properties.
2. Number of Isomers — Number of Isomers increases with increase in number of carbon atoms. [e.g., C₄H₁₀ has two isomers, C₅H₁₂ has three isomers]

Difference between Chain Isomerism and Position Isomerism:
Chain Isomerism occurs due to the difference in arrangemnet of Carbon atoms in the chain whereas Position Isomerism occurs due to the difference in position of functional group.

Isomers of Pentane exhibit chain isomerism:

n-pentane

iso-pentane

Isomers of Butyne exhibit position isomerism:

but-1-yne

but-2-yne