Infrared IR spectroscopy is a powerful analytical technique used to identify functional groups in organic compounds by analyzing the vibrations of chemical bonds within the molecules. It works by passing infrared radiation through a sample and measuring the amount of radiation absorbed at different wavelengths. The absorption of IR radiation corresponds to the energy required to excite the vibrational modes of the chemical bonds in the molecule. Each functional group has a unique set of vibrational frequencies, which can be used as a fingerprint to identify the presence of that functional group in the compound.To determine the identity of a functional group in a given organic compound using IR spectroscopy, follow these steps:1. Prepare the sample: The organic compound must be prepared in a suitable form for IR analysis. This can be done by creating a thin film of the compound on an IR-transparent window such as potassium bromide or sodium chloride or by mixing the compound with an inert solid such as potassium bromide and pressing it into a pellet.2. Obtain the IR spectrum: Place the prepared sample in the IR spectrometer and record the spectrum. The spectrum will display the absorbance or transmittance of the sample as a function of the wavenumber cm or wavelength m of the infrared radiation.3. Analyze the spectrum: Examine the spectrum for characteristic absorption bands that correspond to specific functional groups. These bands are typically found in specific regions of the spectrum, known as the fingerprint region 400-1500 cm and the functional group region 1500-4000 cm . Some common functional groups and their characteristic absorption bands include: - Hydroxyl group OH : Broad absorption around 3200-3600 cm - Carbonyl group C=O : Strong, sharp absorption around 1650-1750 cm - Amine group NH : Medium to strong absorption around 3300-3500 cm primary amines show two peaks, while secondary amines show one peak - Alkene group C=C : Medium absorption around 1600-1680 cm - Alkyne group CC : Medium to strong absorption around 2100-2260 cm - Aromatic ring C=C : Multiple absorptions around 1450-1600 cm4. Compare with reference spectra: To confirm the identity of the functional groups, compare the obtained spectrum with reference spectra of known compounds containing the suspected functional groups. This can be done using spectral libraries or by comparing with literature values.5. Interpret the results: Based on the presence of characteristic absorption bands and comparison with reference spectra, determine the functional groups present in the organic compound. This information can then be used to deduce the structure of the compound or to confirm its identity.