AP BIOLOGY

Detailed explanation-1: -Butane is the smallest alkane to show such isomerism with 2 isomers. Pentane can have 3 isomers.

Detailed explanation-2: -It has two isomers; n-butane and isobutane. Here n-butane is a straight-chain compound with four carbon atoms bonded with single covalent bonds. Another isomer is isobutane or 2-methylpropane in which three carbon atoms from the parent chain and one carbon atom is placed as the side chain at C-2 of the parent chain.

Detailed explanation-3: -Answer and Explanation: A) The smallest alkane possible to have structural isomer is four carbon molecules as if lesser carbons are present then the carbons cannot be arranged differently it will only be a linear chain. Example: Butane has four carbons, it is the smallest hydrocarbon, having structural isomers..

Detailed explanation-4: -Butene consists of four constitutional isomers: 1-butene (alpha-butene), cis-2-butene (cis-beta-butylene), trans-2-butene (trans-beta-butylene), and isobutylene.