Which of the following is NOT terminal alkyne ?

Step-by-step solution

Terminal alkynes have a triple bond at the end of the carbon chain, meaning at least one hydrogen atom is directly attached to a triply bonded carbon atom ( R-C C-H ). Ethyne is H-C C-H , which is a terminal alkyne. Propyne is CH₃-C C-H , which is a terminal alkyne. But-1-yne is CH₃-CH₂-C C-H , which is a terminal alkyne. But-2-yne is CH₃-C C-CH₃ , where the triple bond is between the second and third carbon atoms. It does not have a hydrogen atom attached to the triply bonded carbon atoms. Thus, it is an internal