Question

How many chain isomers are possible for organic compound having molecular formula C₄H₈?

• A. 2
• B. 5
• C. 6
• D. 7

Answer 1

The correct option is B

5

• Isomerism is the phenomenon in which more than one compound has the same chemical formula but different chemical structures. A wide variety of organic compounds can be observed due to this property of carbon.
• Chain isomerism is a phenomenon in which two organic compounds having the same molecular formula exhibit different structural arrangements of carbon atoms in the carbon skeleton or branched chain.
• ${\mathrm{C}}_4{\mathrm{H}}_8$ has 5 isomers,
• The compound is an alkene, with IUPAC name ‘’ Butene''.
• The 5 isomers are

1. 1- Butene ${\mathrm{CH}}_2=\mathrm{CH}-{\mathrm{CH}}_2{\mathrm{CH}}_3$
2. 2-Butene. ${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_3$
3. 2- Methylpropane
4. Cyclobutane
5. Methylcyclopropane

Hence, the correct option is (B) 5 isomers of ${\mathrm{C}}_4{\mathrm{H}}_8$.