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A very nice comprehensive set of IR absorption group frequencies were compiled seventy decades ago in the Journal of Optical Society of America by Colthup, 1950, 40, 397-400. It is freely available if you search "Spectra-structure correlations in the infra-red region" by Colthup in Google Scholar. You should memorize some standard frequencies of ...


In addition to James's answer, you can often tell primary amines and amides apart from OH groups because they will have two peaks in the 3300 - 3500 region. Your sample clearly shows this double peak, suggesting an NH2 group. Combined with the strong c=o absorbance at 1700 and you have an amide.


First, eliminate ethylene (ethene) because the strong absroption from 3200 to 3600 requires $-OH$ or $-NH$. Ethanol could be suggested by the 3200-3600, but lacks a strong absorption at 1050-1410, so eliminate ethanol. The strong peak at 1700 suggests acid or amide $C=O$. The lack of strong absorption between 2500-3000 eliminates carboxylic acid, so the ...

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