Infrared Spectroscopy Table - Online Tutor, Practice Problems & Exam Prep

Which of the two C―O bonds in propoxybenzene produces a C―O stretching band at a higher wavenumber, and which produces a band at a lower wavenumber? What characteristic causes these bands to be intense?

Consider the following reaction: 

The absence of what band in the IR spectrum of the product indicates that the carboxylic acid was completely converted to an acid chloride?

Predict the significant bands present in the IR spectrum of the given compound.

Predict the important peaks present in the IR spectrum of the molecule shown below.

The following reaction shows the conversion of a carboxylic acid to an ester: 

How could IR spectrum information be used to prove that the reaction was successful?

The following reaction shows the isomerization of alkene A to a more stable alkene B under acidic conditions:

How could IR spectroscopy be used to differentiate them?

The following acid-catalyzed hydrolysis of an ester produces equal amounts of alcohol and carboxylic acid:

After separation, how could IR spectroscopy be used to differentiate between the alcohol and carboxylic acid?

The IR spectrum of the product of the following reduction reaction suggested that it contained a mixture of the starting amide and the desired amine. 

After separation, how could IR spectroscopy be used to differentiate them?

How can the following compounds be differentiated using IR spectroscopy?

Differentiate the following compounds using IR spectroscopy?

Determine the class of compound that contains C—O bond, shows no absorption band at 3200 cm⁻¹ and no absorption bands at around 1700 cm⁻¹ or between 2250 cm⁻¹ and 2200 cm⁻¹?

Specify the characteristic difference in IR spectroscopy absorption bands between each pair of compounds given below.

I) a carboxylic acid and an alcohol
II) a cyclic ester and an open chain ester

What is the characteristic difference in IR absorption bands between the following pair of compounds?

I) Propene and propyne
II) A secondary amine and an amide

Specify the characteristic absorption band that can be used to distinguish between the following pair of compounds.

Determine the characteristic IR absorption band that can be used to distinguish between the following pair of compounds.

Provide one IR absorption band that can be used to distinguish between the following pairs of compounds.

Determine how IR spectroscopy can be used to confirm that the following reaction has been completed. Also, how could you confirm that all of the NH₂—NH₂ was removed after purification?

How can 1-butene, 1-butyne, and 2-butyne be distinguished using IR spectroscopy?

Rank the compounds given below in order of decreasing wavenumber for the C=O absorption peak in the IR spectra:

Rank the compounds given below in order of decreasing wavenumber for the highlighted C—O bond absorption peak in the IR spectra:

Provide wavenumbers for the main IR absorption bands that each of the compounds given below would produce:

Norlutin and Enovid are ketones that prevent ovulation, making them effective contraceptives. Which of the following claims about the carbonyl absorption (C=O stretch) of these two compounds in the infrared spectrum is accurate?

Describe how the IR spectrum of the products would be used to differentiate them from the reactants in the following three reactions.

Suggest the peaks of the IR spectrum to identify the functional groups for each of the compounds given below.
a. butyl amine
b. hexanoic acid
c. hex-1-yne

Each of the structures below has distinct IR absorption. Match all these structures to their respective distinct absorptions.

IR absorptions:
i. Strong peak at 1715 cm^–1
ii. Strong peak at 2250 cm^–1
iii. Very broad peak at 3300 cm^–1

An unsaturated carboxylic acid (E)-but-2-enoic acid, has a broad peak at 3400cm^–1, and two sharp peaks at 1695 cm^–1 and 1650cm^–1 in the IR spectrum.
Explain and highlight the characteristics that make it evident that the acid is unsaturated and conjugated.

Suggest the peaks of the IR spectrum to identify the functional groups for each of the compounds given below.
a. Cyclopentene
b. Hexan-2-ol
c. Hexan-2-one

Determine the Infrared peaks that correspond to each of the following four compounds and explain how these peaks are related to the structure of each compound.

a. Medium peak at 2900 cm^-1, and a strong peak at 1715 cm^-1.

b. Medium peak at 3000cm^-1, a weak peak at 2250 cm^-1, and a weak overtone at 1600 cm^-1

c. Strong, broad 3000 cm^-1, a strong peak at 1690 cm^-1, and a weak peak at 1675 cm^-1

d. Strong, broad 3200 cm^-1, medium peak at 2900 cm^-1, and a weak overtone at 1600 cm^-1

Consider the dehydration of cyclopentanol to cyclopentene in the lab.
a. Provide the IR spectrum peaks to determine whether the product is pure or a compound mixture.
b. Explain why the choice of mass spectrometry may be inadequate to that of IR spectroscopy..

Identify the functional group(s) (alcohol, amine, ketone, aldehyde, or carboxylic acid) present in each unknown compound whose major IR peaks are listed below.

Compound A:  3300 cm^-1 (two spikes)
Compound B: 3400 cm^-1 (broad peak), 1710 cm^-1 (strong peak), and 3000 cm^-1.
Compound C: 3330 cm^-1 (Strong broad peak), and 3000 cm^-1.

Identify the functional group(s) (conjugated ketone, ester, amide, nitrile, and alkyne) present in each unknown compound whose major IR peaks are listed below.

Compound A: 3165 cm^–1, 3000 cm^–1, and 1660 cm^-1
Compound B: 3050 cm^–1 (small peak), 1680 cm^–1 (strong peak)
Compound C: 1740 cm^-1 ,and 1260 cm^-1

True or false. Undiluted propanol exhibits an O−H stretch at a larger wavenumber than propanol dissolved in tetrachloroethylene.