Question

How can I distinguish the functional group region and the finger print region in the infrared spectrum?

Answer 1

In order to distinguish the functional group region and the fingerprint region present in the infrared spectrum, we must first know what an infrared spectrum is. Infrared also known as the infrared light, which is a type of electromagnetic radiation whose radiation is longer than the wavelength of the visible light.

Complete answer:
Let us first understand about the infrared spectrum. Infrared also known as the infrared light, which is a type of electromagnetic radiation whose radiation is longer than the wavelength of the visible light. The frequency of the infrared spectroscopy will range from 400-4000 $c{m^{ - 1}}$.
Let us now discuss the fingerprint region. In the infrared spectrum the region between 1450-500 $c{m^{ - 1}}$ is known as the fingerprint region. In the fingerprint region the number of bending vibrations are more compared to the number of stretching vibrations. Small change in the structure and constitution of the molecule will give significant change in the absorption band. Many compounds having unique absorption band in this region helps in the identification of the compound.
In the infrared spectrum, the region ranging from 4000-1450 $c{m^{ - 1}}$ is called the function group region. When there is a stretching vibration between hydrogen and any other atom whose mass is less than 19, then there will be an appearance of strong absorption band between 2500-4000 $c{m^{ - 1}}$. The functional group region will vary with a narrow range. Different functional groups will be having different stretching vibrations. We should be aware of different stretching vibrations of various functional groups.

Note:
We have to remember that not only infrared spectrum, there are also other electromagnetic radiations present they are:
- Ultraviolet light
- Visible light
-Microwaves
- Radio waves
- X-rays
- Gamma rays