A-LevelChemistryAnalytical techniques9701/12 · Oct/Nov 2025 · Q401 Mark

The purity of a compound can be determined using infrared spectroscopy. The table gives the characteristic infrared absorption frequencies for some selected bonds. [Figure 40: Table of IR absorption frequencies] Propan-2-ol is made by hydration of propene. A sample of the product is obtained. Which feature of the infrared spectrum of the product would show that no propene remains in the product?

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Aabsorption in the 2900 cm⁻¹ region

Bstrong absorption below 1000 cm⁻¹

Cthe lack of absorption at or near 1250 cm⁻¹

Dthe lack of absorption at or near 1550 cm⁻¹

✓ Correct answer

D: the lack of absorption at or near 1550 cm⁻¹

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Topic: Analytical techniques, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2025 Paper 1 Variant 2, question 40.

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