Spectroscopic analysis of alkynes:

The IR spectrum of an alkyne depicts a characteristic triple bond absorption in the region 2260-2100 cm^-1. This can frequently be weak and if the alkyne is symmetrical no absorption will be seen at all. Even though the absorption may be weak, it can generally be identified because the relevant region is generally devoid of peaks.

Terminal alkynes depict absorption at 3300 cm^-1 because of C-H stretching. This is sharper than absorptions because of O-H or N-H stretching. The proton of a terminal alkyne typically provides a signal at 1.8-3.1 ppm in the ¹Hnmr, whereas the carbons of any alkyne come out in the region 70-95 ppm in the ¹³C nmr.