Question

Structural isomerism in a saturated hydrocarbon is due to

• A. change in the valency of carbon.
• B. change in the ratio of elements in compounds.
• C. formation of branches in the chain of C atoms.
• D. formation of double bond.

Answer 1

The correct option is C

formation of branches in the chain of C atoms.

Compounds with identical molecular formula but different structures are called structural isomers. If the ratio of elements changes, so does the molecular formula. If a double bond is formed, two H atoms shall disappear from the molecule. Hence,only branching does not affect the molecular formula.

n-butane (C₄H₁₀) and iso-butane(C₄H₁₀) are structural isomers with same molecular formula but different structural formula.