IB Chemistry HL 3.2.9 Infrared Spectroscopy Question Bank

Practise HL 3.2.9 infrared spectroscopy by reading structural and spectroscopic evidence, then selecting the explanation supported by the data.

Exam points

identify the diagnostic structural or spectral feature
match peaks, splitting or stereochemical relationships to the correct structure
combine independent evidence before making the final deduction

[Maximum number: 2]

Urea, $\left(\mathrm{H}_{2} \mathrm{~N}\right)_{2} \mathrm{CO}$ , is excreted by mammals and can be used as a fertilizer.

The IR spectrum of urea is shown below.

Figure for Question 3.2.9 (HL)—Infrared spectroscopy question 1 — IB Chemistry HL

Identify the bonds causing the absorptions at $3450 \mathrm{~cm}^{-1}$ and $1700 \mathrm{~cm}^{-1}$ using section 26 of the data booklet.

$3450 \mathrm{~cm}^{-1}$ :

$1700 \mathrm{~cm}^{-1}$ :

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3.2.9 (HL)—Infrared spectroscopy question 1