MHT CET Chemistry Question (2026) — Solution

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 CH_3-C C-H, which is a terminal alkyne. But-1-yne is CH_3-CH_2-C C-H, which is a terminal alkyne. But-2-yne is CH_3-C C-CH_3, 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 alkyne, not a terminal alkyne. Answer: But - 2 - yne