Identify which carbonyl group will exhibit a signal at a lower wavenumber

The IR spectrum of trans-oct-2-enoic acid is shown. Point out the spectral characteristics that allow you to tell that this is a carboxylic acid, and show which features lead you to conclude that the acid is unsaturated and conjugated.

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Following a LiAlH₄ reduction, an IR spectrum suggested that the product was a mixture of the starting amide and the desired amine.

(b) Once separated, how could you distinguish between the amide and the amine using IR spectroscopy?

Which shows an O–H stretch at a larger wavenumber: ethanol dissolved in carbon disulfide or an undiluted sample of ethanol?

Answer each of the following questions based on the images below.

a) Which compounds show an intense peak ~ 1700 cm^-1?

b) Which compound shows an intense, broad peak at ~ 3400 cm^-1?

c) Which compound has a peak at ~1700 cm^-1, but no peaks at 2700 cm^-1?

d) Which compound has no signal beyond the fingerprint region?

The infrared spectra for three compounds are provided. Each compound has one or more of the following functional groups: conjugated ketone, ester, amide, nitrile, and alkyne. Determine the functional group(s) in each compound, and assign the major peaks above 1600 cm^–1.

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Spectra are given for three compounds. Each compound has one or more of the following functional groups: alcohol, amine, ketone, aldehyde, and carboxylic acid. Determine the functional group(s) in each compound, and assign the major peaks above 1600 cm^–1.

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