Vibrational Spectroscopy – Pharmacognosy & Phytochemistry
1. Vibrational spectroscopy involves the transitions falling in the spectral range of _______
A.100-1000 cm
B. 300-3000 cm
C. 400-4000 cm
D. 500-5000 cm
Answer:- C
Explaination: Vibrational spectroscopy involvesthe transitions falling in the spectral range of 400-4000 cm-1(infrared region).
2.Which ofthe region of IR spectra appears between (1400-600)cm ?
A. Functional group region
B. Finger print region
C. Low-frequency region
D.None ofthe mentioned
Answer:- B
Explaination: Finger print region of IR spectra appears between (1400-600)
3. Select the correct statement from the following option.
A. Infrared spectra can identify the unknown materials
B. Itcan determine the amount of componentsin a mixture
C. It can also determine the quality of a sample
D.All ofthe mentioned
Answer:- D
Explaination: Infrared spectra can identify the unknown materials. Itcan determine the amount of componentsin a mixture and can also determine the quality of a sample.
4.Which ofthe following molecule have infrared active vibrations?
A.NO
B. CH
C. H
D.All ofthe mentioned
Answer:- A
Explaination:NO molecule have infrared active vibrations. Infrared spectra can identify unknown materials. Itcan determine the amount of componentsin a mixture and can also determine the quality of a sample.
5.Which ofthe following cannot show a vibrational absorption spectrum?
A.OCS
B.HO
C. CO2
D. CH= CH
Answer:- D
Explaination: CH= CH cannotshow vibrational absorption spectrum. OCS,H2O and CO2 can show a vibrational absorption spectrum.
6.Which ofthe following is not a type of bending molecular vibration?
A. Twisting
B. Stretching
C. Wagging
D. Rocking
Answer:- B
Explaination: Stretching is not a type of bending molecular vibration. Twisting, wagging and rocking are types of bending molecular vibration.
7.What is the absorption frequency (cm ) of –C=N functional group?
A. 3610-3640
B.1690-1760
C. 1180-1360
D. 2850-2960
Answer:- C
Explaination: The absorption frequency for –C=N group is 1180-1360 cm-1.Absorption spectroscopy refersto spectroscopic techniques that measure the absorption of radiation, as a function of frequency or wave length, due to its interaction with a sample.
8. Presence of a functional group in a compound can be established by using _________
A. Chromatography
B. IR spectroscopy
C. Masss pectroscopy
D. X-ray diffraction
Answer:- B
Explaination: Presence of a functional group in a compound can be established by using IR spectroscopy. It is the spectroscopy that deals with the infrared region ofthe electromagnetic spectrum,thatislight with a longer wave length and lower frequency than visible light.
9. Selectthe incorrect option from the following option.
A. IR spectroscopy helpsin the determination of purity
B. IR spectroscopy helpsin the determination of force constantfrom vibrational spectrum
C. IR spectroscopy help sin identifying an unknown compound
D.None of the mentioned
Answer:- D
Explaination: All the options are correct. IR spectroscopy helpsin the determination of purity, force constantfrom the vibrational spectrum and identifying an unknown compound.
10. IR spectroscopy helpsin detecting the presence of hydrogen bonding.
A. True
B. False
C. Incomplete statement
D.Unpredictable
Answer:- A
Explaination: IR spectroscopy helpsin detecting the presence of hydrogen bonding. Itisthe spectroscopy that deals with the infrared region of the electromagnetic spectrum,thatislight with a longer wavelength and lowerfrequency than visible light.
