Q6. Which of the compounds below would give the following IR spectrum?

Background

Topic: IR Spectroscopy and Functional Group Identification

This question tests your ability to interpret IR spectra and match them to the correct organic compound based on functional group absorptions.

Key Terms and Formulas

• IR Spectroscopy: A technique used to identify functional groups in organic molecules by measuring absorption of infrared light at specific wavenumbers.

• Wavenumber (cm-1): The frequency of IR light absorbed, characteristic of certain bonds.

• Key absorptions:

  • C≡N (nitrile) stretch: cm-1

  • O-H (alcohol/phenol) stretch: cm-1

  • N-H stretch: cm-1

Step-by-Step Guidance

1. Examine the IR spectrum for prominent peaks. Notice the strong absorption near $2249$ cm-1, which is characteristic of a nitrile (C≡N) group.

2. Check for other significant peaks. There is no broad O-H stretch (which would appear around cm-1), nor is there a sharp N-H stretch near $3300$ cm-1.

3. Compare the spectrum to the possible compounds listed in the question. Look for the compound that contains a nitrile group (C≡N) and lacks O-H or N-H groups.

4. Review the molecular structure options and identify which one matches the functional groups indicated by the IR spectrum.

Try solving on your own before revealing the answer!