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WorksheetsFTIR SPECTROSCOPY
Total questions: 15
Worksheet time: 15mins
In the following compound, rank the highlighted bonds in terms of increasing wavenumber:
A < B < C
C < A < B
C < B < A
A < C < B
In what region of the spectrum does infrared radiation occurs?
Between the visible and ultraviolet regions
Between the visible and microwave regions
Between the visible and x-ray regions
Between ultraviolet and gamma regions
Which of the following molecules can’t be analysed by IR
FeCl3
H2O
Cl2
CH3OH
Which of the following bending vibration takes place in different planes.
Asymmetric stretching
Rocking
Scissoring
Twisting
According to Hook’s law which of the following linkages will have more force constant?
P
Q
R
P and R will have equal and greater force constant
The infrared spectrum was obtained from a compound and showed absorptions at 2100 cm-1,
1700 cm-1, and 1200 cm-1. Identify the compound.
CH3COOCH3
C6H5COOH
CH2=CHCH2OH
CH≡CCH2CO2CH3
A molecule absorbs IR at a wavenumber of 1720 cm-1. Which functional group could account for this absorption.
Aldehydes
Carboxylic Acids
Ethers
Alcohols
Which of the following statements about infrared spectroscopy is correct?
Infrared spectroscopy can be used to determine the size and shape of a compound’s carbon skeleton.
An IR spectrometer illuminates a compound with infrared light and records the positions where the light is blocked by the compound. This results in the peaks of the spectrum.
The fingerprint region of the spectrum can be used to identify functional groups.
When the frequency of infrared light matches the frequency of bond vibration in a molecule, a peak appears on the spectrum.
Which is belongs to fingerprint region?
2500-4000
2000 - 2500
1500 - 2000
500 - 1500
What type of transitions mainly occur in infrared spectroscopy?
Electronic transitions only
Rotational and vibrational transitions
Rotational transitions only
All the electronic, rotational, vibrational transitions
Which functional group is likely to absorb IR radiation at a wavenumber of 3000 cm-1?
Alcohols
Aldehydes
Carboxylic Acids
Ethers
Explain the significance of the fingerprint region in an infrared spectrum.
It helps in identifying the size and shape of a compound's carbon skeleton.
It provides information about the functional groups present in a compound.
It is unique for each compound and can be used for compound identification.
It indicates the presence of impurities in the sample.
In an IR spectra of 1-octyne and 4-octyne, the IR spectra of 4-octyne does not have the alkyne stretch absorption peak. The reason for this observation is that _______________________________________________.
conjugation moves stretch to lower frequency
4-octyne reacts with KBr while 1-octyne does not
4-octyne has symmetrically substituted triple bond while 1-octyne does not
4-octyne is inactive in IR range whereas 1-octyne is highly active.
An organic compound shows two peaks at 1820 and 1750 cm-1. The functional group presents in the compound is____________
Acid anhydride
Ketone
Carboxylic acid
Acid chloride
In a solid sample treatment technique, the finely ground solid sample is mixed withmineral oil to make a thick paste which is then spread between IR transmitting windows.What is the name of this solid sample treatment technique?
Pressed pellet
Mull technique
Solid films
Solid runs in solution
