H ydrocarbons that contain carbon-carbon triple bond are called alkynes. Non- cyclic alkynes have the molecular formula C, H2n-2. Acetylene (HCCH) is th simplest alkyne. We call compounds that have their triple bond at the end of a carbon chain(RC=CH) monosubstituted, or terminal, alkynes. Disubstituted alkynes (RCCR') are said to have internal triple bonds. You will see in this chapter that a car- bon-carbon triple bond is a functional group, reacting with many of the same reagents