Infrared IR spectroscopy is a powerful analytical technique used to identify functional groups in organic compounds by analyzing the absorption of infrared radiation by the molecule. The absorption of IR radiation causes molecular vibrations, such as stretching and bending, which are characteristic of specific functional groups.To identify the functional group present in an unknown organic compound using IR spectroscopy, follow these steps:1. Obtain the IR spectrum of the unknown compound: Run the sample through an IR spectrometer to obtain the spectrum, which will display the absorbance or transmittance of the compound at various wavenumbers measured in cm .2. Analyze the spectrum: Examine the spectrum for characteristic absorption bands that correspond to specific functional groups. Some important regions to focus on are: a. 4000-2500 cm: This region is known as the functional group region and contains absorptions related to O-H, N-H, and C-H bonds. b. 2500-1500 cm: This region is known as the fingerprint region and contains absorptions related to C=O, C=C, CC, and CN bonds.3. Compare the absorption bands to known functional groups: Use a reference table or literature to compare the observed absorption bands with the characteristic bands of known functional groups. Some common functional groups and their characteristic IR absorption bands are: a. O-H: Broad absorption around 3300-3600 cm alcohols, carboxylic acids b. N-H: Sharp absorption around 3300-3500 cm amines, amides c. C-H: Absorption around 2850-3000 cm alkanes, alkenes, alkynes d. C=O: Strong absorption around 1650-1750 cm ketones, aldehydes, carboxylic acids, esters, amides e. C=C: Absorption around 1600-1680 cm alkenes f. CC: Absorption around 2100-2260 cm alkynes g. CN: Absorption around 2210-2260 cm nitriles 4. Identify the functional group: Based on the comparison of the observed absorption bands with the characteristic bands of known functional groups, identify the functional group s present in the unknown organic compound.Keep in mind that some compounds may have multiple functional groups, and the presence of one functional group may affect the absorption bands of another. Additionally, the exact position and intensity of absorption bands can be influenced by factors such as molecular structure, conjugation, and hydrogen bonding. Therefore, it is essential to consider the entire spectrum and use additional analytical techniques, if necessary, to confirm the identity of the functional group s present in the unknown compound.