IR spectroscopy is an exceedingly useful analytical technique for determining the presence of certain bonds, and hence functional groups, in a molecule. Bonds absorb specific frequencies of IR radiation, causing them to vibrate more strongly. An IR spectrum for a molecule shows us which frequencies have been absorbed and with the use of a data sheet we can determine the types of bond present.
The first of these posts explains the background chemistry before a deep dive into how to interpret an IR spectrum at A level, with plenty of practice exam questions.
What is infrared spectroscopy?
A complete explanation of the theory behind IR spectroscopy from vibrating bonds, symmetric and asymmetric stretches to an IR spectrum
Interpreting an IR spectrum
Everything you need to know, exam tips and terminology and exam style practice questions
Why are there so many different C=O bond vibrations in an IR spectrum?
It all depends on the functional group …
Mixed spectra long answer questions
This is a set of more difficult long answer exam questions that require you to use data from mass spectra, IR spectra, 1H NMR and 13C NMR spectra to deduce the structure of a molecule.
They are notoriously poorly answered by students, so hopefully the model answers and exam tips here will help you power through!