Practice question

Infrared stretching frequency increases with bond strength, described by force constant k in Hooke's law. Among carbon linkages, triple bond possesses three shared electron pairs, strongest bond, highest force constant, thus highest wavenumber around 2100-2260 cm-1. Double bonds C=C and C=O absorb near 1650 and 1710 cm-1 respectively, single C-C bonds below 1200 cm-1. Although O-H and N-H stretches appear even higher near 3300-3600 cm-1 due to light hydrogen mass, within listed carbon bonds C≡C absorbs at highest frequency, valuable for identifying alkyne-containing natural products and modified amino acids.