Which of the following is the structural formula for 1-butyne?

The correct answer is indeed the structural formula for 1-butyne, which can be denoted as CH≡C-CH₂-CH₃.

1-butyne is an alkyne, meaning it contains a carbon-carbon triple bond. In this case, the positioning of the triple bond at the first carbon indicates that it is a terminal alkyne, which is a characteristic feature of 1-butyne. The structure showcases a three-carbon chain with the first carbon involved in the triple bond, followed by a two-carbon extension, accurately representing 1-butyne.

The first part of the structure, CH≡C, indicates the presence of a triple bond between the first two carbons. The subsequent CH₂ and CH₃ groups show that this triple bond is at the terminal end of the carbon chain, consistent with the nomenclature of 1-butyne.

This structural representation effectively captures the molecular arrangement and the connectivity between atoms, serving as a clear indication of this particular alkyne’s identity.