CBSE Class 10 Answered

ISOMERS

Compounds having same molecular formula but different structural formula are known as isomers and the phenomenon as isomerism.

E.g. Butane and isobutane are two different compounds  with same molecular formula C₄H₁₀.

Causes of Isomerism

1. Difference in the mode of linking of atoms.

2. Difference in the arrangement of atoms or groups in space.

Different types of Structural Isomerism

(i)Chain isomerism:

Two or more compounds which have a similar molecular formula but different arrangement of carbon atoms in straight or branched chains, such compounds are referred to as chain isomers and the phenomenon as chain isomerism.

(ii)Position isomerism:

When two or more compounds with the same molecular formula differ in the position of substituent atom or functional group on the carbon atom, they are called position isomers and the phenomenon as position isomerism.

(iii) Functional isomerism:

Two or more compounds with the same molecular formula but different functional groups are called functional isomers and the phenomenon as functional isomerism.

(iv)Metamerism:

It arises due to unequal distribution of alkyl groups on either side of the functional groups in the molecules.