Chemistry - Nomenclature Question with Solution | TestHub

Question Explanation:

Identify the molecule that is an isomer of the entire given set of compounds having the molecular formula ${\mathbf{C}}_5{\mathbf{H}}_{10}$.

Concept:

This question is based on isomerism, degree of unsaturation, and the general formulas of alkenes and cycloalkanes.

Both alkenes and cycloalkanes follow the general formula ${\mathbf{C}}_{\mathbf{n}}{\mathbf{H}}_{2n}$, so different structural arrangements can exist with the same molecular formula.

Solution:

All compounds listed in the common set—such as cyclopentane, methylcyclobutane,   pentene etc. —have the molecular formula C₅H₁₀ , making them structural isomers of one another.

Option (4): This compound is 2-methyl-2-butene , an alkene containing five carbon atoms. Its molecular formula is also C₅H₁₀ , so it is an isomer of all compounds in the given set.

Other options: These either contain a different number of carbon atoms or have a different degree of unsaturation, so they do not match the formula C₅H₁₀ .

Final Answer: Option (D)