Instrumental Analysis Final Exam Review questions with
verified answers
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours)
what is the splitting pattern for the -OH in C-13 NMR? Ans✓✓✓ (none
of the above)
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) what is the splitting pattern for the -CH2-
carbon in hydrogen decoupled C-13 NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the -CH2-
hydrogens in proton NMR? Ans✓✓✓ 1:3:3:1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the -OH
hydrogens in hydrogen NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
,atmosphere for 3 hours) what is the splitting pattern for the CH3-
carbon in hydrogen decoupled C-13 NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the CH3-
hydrogens in proton NMR Ans✓✓✓ 1:2:1
1H NMR rule Ans✓✓✓ equivalent nuclei do not interact with one
another to give multiple absorption peaks
J decreases with 1H separation and seldom seen >3 bond lengths
multiplicity of a band is determined by the number (n) of equivalent 1H
on neighboring atoms and is given by (n+1)
if 1HB are affected by 1HA and 1HC, the multiplicity of B is (nA+1)(nC+1)
areas under a multiplet are symmetric about the midpoint and given by
pascal's triangle
J is independent of B
, a deuterated lock solvent is used in NMR to Ans✓✓✓ keep the
magnetic field from drifting
a mass spectrum produced by electron impact ionization of an organic
sample displays a molecular ion peak at 78 and a base peak at 78. the
molecule could be? Ans✓✓✓ benzene
a mass spectrum produced by electron impact ionization of an organic
sample displays a molecular ion peak at 92 and a base peak at 91. the
molecule could be? Ans✓✓✓ toluene
a material containing which type of absorption would make the best
ink? Ans✓✓✓ charge transfer
a material with which type of absorption (only) would make a good
invisible ink? Ans✓✓✓ n to sigma*
a molecule has a singlet ground state and has the following absorption,
fluorescence, and phosphorescence spectra. predict the energy level
diagram of the molecule Ans✓✓✓ A
a photon may be absorbed by an atom when the energy of the photon
is ___ the energy difference between the ground state energy level and
an excited energy level Ans✓✓✓ equal to
verified answers
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours)
what is the splitting pattern for the -OH in C-13 NMR? Ans✓✓✓ (none
of the above)
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) what is the splitting pattern for the -CH2-
carbon in hydrogen decoupled C-13 NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the -CH2-
hydrogens in proton NMR? Ans✓✓✓ 1:3:3:1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the -OH
hydrogens in hydrogen NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
,atmosphere for 3 hours) what is the splitting pattern for the CH3-
carbon in hydrogen decoupled C-13 NMR? Ans✓✓✓ 1
(The following questions refer to the NMR spectrum of an ethanol CH3-
CH2-OH sample which has been exposed to a high humidity
atmosphere for 3 hours) What is the splitting pattern for the CH3-
hydrogens in proton NMR Ans✓✓✓ 1:2:1
1H NMR rule Ans✓✓✓ equivalent nuclei do not interact with one
another to give multiple absorption peaks
J decreases with 1H separation and seldom seen >3 bond lengths
multiplicity of a band is determined by the number (n) of equivalent 1H
on neighboring atoms and is given by (n+1)
if 1HB are affected by 1HA and 1HC, the multiplicity of B is (nA+1)(nC+1)
areas under a multiplet are symmetric about the midpoint and given by
pascal's triangle
J is independent of B
, a deuterated lock solvent is used in NMR to Ans✓✓✓ keep the
magnetic field from drifting
a mass spectrum produced by electron impact ionization of an organic
sample displays a molecular ion peak at 78 and a base peak at 78. the
molecule could be? Ans✓✓✓ benzene
a mass spectrum produced by electron impact ionization of an organic
sample displays a molecular ion peak at 92 and a base peak at 91. the
molecule could be? Ans✓✓✓ toluene
a material containing which type of absorption would make the best
ink? Ans✓✓✓ charge transfer
a material with which type of absorption (only) would make a good
invisible ink? Ans✓✓✓ n to sigma*
a molecule has a singlet ground state and has the following absorption,
fluorescence, and phosphorescence spectra. predict the energy level
diagram of the molecule Ans✓✓✓ A
a photon may be absorbed by an atom when the energy of the photon
is ___ the energy difference between the ground state energy level and
an excited energy level Ans✓✓✓ equal to
