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4.8 Infrared Spectroscopy Problems

Last updated

Feb 11, 2023
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- 4.7 Identifying Characteristic Functional Groups
- 4.9: Application

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Learning Objectives

After completing this section, you should be able to

determine functional groups in an IR spectrum

Here are some problems for IR analysis.

Exercise $\PageIndex{1}$

What functional group is present in the spectrum below?

Answer: Alkyne

Exercise $\PageIndex{2}$

What functional group is present in the spectrum below?

Answer: Carboxylic Acid

Exercise $\PageIndex{3}$

Which IR spectrum goes with which molecule below?

Molecule A:

Molecule B:

IR spectrum 1:

IR spectrum 2:

Answer

Molecule A is Spectrum 2.

Molecule B is Spectrum 1.

Exercise $\PageIndex{4}$

What notable peaks in the IR spectrum verify that benzaldehyde is present?

Answer

Frequency (cm^-1)	Functional Group
3063	Csp2-H
2818 and 2736	aldehyldic proton
1695	C=O
1653-1455	aromatic ring

Learning Objectives

Exercise 1\PageIndex{1}

Exercise 2\PageIndex{2}

Exercise 3\PageIndex{3}

Exercise 4\PageIndex{4}

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Exercise $\PageIndex{1}$

Exercise $\PageIndex{2}$

Exercise $\PageIndex{3}$

Exercise $\PageIndex{4}$