The correct answer is C. 2-methylbutane.
Isopentane is a branched-chain saturated hydrocarbon with the chemical formula C5H12. It is a colorless, flammable liquid with a peppermint-like odor. It is used as a fuel, a solvent, and a chemical intermediate.
2-methylbutane is the most common isomer of isopentane. It is a structural isomer of n-pentane, which has a straight chain. 2-methylbutane has a branched chain, which makes it more stable than n-pentane.
The other options are incorrect.
A. Dimethylbutane is a structural isomer of isopentane. It has two methyl groups attached to a central carbon atom.
B. Isobutane is a structural isomer of isopentane. It has a methyl group attached to a secondary carbon atom.
D. Butadiene is an unsaturated hydrocarbon with the chemical formula C4H6. It is a colorless, flammable liquid with a strong odor. It is used to make synthetic rubber, plastics, and other chemicals.