Molecular Spectroscopy

ABC26PH1091 · A molecule, AX, has a vibrational energy of 1000 cm-1 and rotational energy of 10 cm-1. Another molecule, BX, has a vibrational energy of… · JUNE 2011

ABC26PH0103 · At room temperature, which molecule has the maximum rotational entropy? · JUNE 2011 self-practice

ABC26PH1092 · At room temperature, which molecule has the maximum rotational entropy? · JUNE 2011

ABC26PH0105 · The Q band in the vibrational spectrum of acetylene is observed in the · DEC 2011

ABC26PH1094 · The Q band in the vibrational spectrum of acetylene is observed in the · JUNE 2011

ABC26PH1095 · In IR spectrum of [Co(CN)5H]3- the Co–H stretch is observed at 1840 cm-1. The (Co–D) stretch in [Co(CN)5D]3- will appear at nearly · JUNE 2011

ABC26PH1104 · The absorption spectrum of O2 shows a vibrational structure that becomes continuum at 56875 cm-1. At the continuum, it dissociates into one… · DEC 2012

ABC26PH1107 · In NMR spectroscopy, the product of the nuclear 'g' factor (gN), the nuclear magneton (beta N) and the magnetic field strength (B0) gives… · JUNE 2013

ABC26PH1109 · The molecule with the smallest rotation partition function at any temperature among the following is: · DEC 2013

ABC26PH0109 · The atomic masses of fluorine and hydrogen are 19.0 and 1.0 amu, respectively (1 amu = 1.67 × 10-27 kg). The bond length of HF is 2.0 Å… · DEC 2019

ABC26PH1111 · The C=O bond length is 120 pm in CO2. The moment of inertia of CO2 would be close to (masses of C and O are 1.9 × 10-27 kg and 2.5 × 10-27… · DEC 2013

ABC26PH1115 · The symmetric rotor among the following is · JUNE 2015

ABC26PH1116 · The nuclear g-factors of 1H and 14N are 5.6 and 0.40 respectively. If the magnetic field in an NMR spectrometer is set such that the proton… · JUNE 2015

ABC26PH1118 · If the reduced mass of a diatomic molecule is doubled without changing its force constant, the vibrational frequency of the molecule will be · DEC 2015

ABC26PH1121 · The vibrational frequency of a homo-nuclear diatomic molecule is nu. The temperature at which the population of the first excited state… · DEC 2015

ABC26PH1122 · The 1H NMR frequency at 1.0T is 42.4 MHz. If the gyromagnetic ratios of 1H and 13C are 27 × 107 and 6.75 × 107T-1S-1 respectively, what… · DEC 2015

ABC26PH1124 · Upon application of a weak magnetic field, a line in the microwave absorption spectrum of rigid rotor splits into 3 lines. The quantum… · JUNE 2016

ABC26PH0112 · 1H NMR spectrum of an organic compound recorded on a 500 MHz spectrometer showed a quartet with line positions at 1759, 1753, 1747, 1741… · DEC 2016 self-practice

ABC26PH1125 · 1H NMR spectrum of an organic compound recorded on a 500 MHz spectrometer showed a quartet with line positions at 1759, 1753, 1747, 1741… · DEC 2016

ABC26PH0113 · Vibrations of diatomic molecules are usually modelled by a harmonic potential. If the potential is given by x2, the correct statement is · DEC 2016 self-practice

ABC26PH1126 · Vibrations of diatomic molecules are usually modelled by a harmonic potential. If the potential is given by x2, the correct statement is · DEC 2016

ABC26PH1127 · The transition that belongs to the Lyman series in the hydrogen-atom spectrum is · DEC 2016

ABC26PH0114 · The rotational constant and the fundamental vibrational frequency of HBr are, respectively, 10 cm-1 and 2000 cm-1. The corresponding values… · DEC 2016

ABC26PH1128 · The rotational constant and the fundamental vibrational frequency of HBr are, respectively, 10 cm-1 and 2000 cm-1. The corresponding values… · DEC 2016

ABC26PH0115 · In a 200 MHz NMR spectrometer, a molecule shows two doublets separated by 2 ppm. The observed coupling constant is 10 Hz. The separation… · DEC 2016

ABC26PH1130 · In a 200 MHz NMR spectrometer, a molecule shows two doublets separated by 2 ppm. The observed coupling constant is 10 Hz. The separation… · DEC 2016

ABC26PH0117 · For a certain magnetic field strength, a free proton spin transition occurs at 700 MHz. Keeping the magnetic field strength constant the… · JUNE 2017 self-practice

ABC26PH1132 · For a certain magnetic field strength, a free proton spin transition occurs at 700 MHz. Keeping the magnetic field strength constant the… · JUNE 2017

ABC26PH1136 · The pair that contains a spherical top and a symmetric top, among the following, is · DEC 2017

ABC26PH1137 · The g-factors of 1H and 13C are 5.6 and 1.4 respectively. For the same value of the magnetic field strength, if the 1H resonates at 600… · DEC 2017

ABC26PH1139 · A symmetric top molecule, among the following, is · JUNE 2018

ABC26PH1142 · The correct statements about HCl and DCl, among the following is · JUNE 2019

ABC26PH0119 · The frequency of O-H stretch occurs at ~ 3600 cm-1. The O-D stretch frequency (in cm-1) would be closest to · 2011-2020 self-practice

ABC26PH1144 · The frequency of O – H stretch occurs at ~ 3600 cm-1. The O – D stretch frequency (in cm-1) would be closest to · DEC 2019

ABC26PH0120 · In the pure rotational microwave spectrum of a XY molecule, the adjacent lines are separated by 4 cm-1. If the molecule is irradiated by a… · 2011-2020 self-practice

ABC26PH1146 · The equilibrium dissociation energy of a diatomic molecule is 4.75 eV and its stretching frequency corresponds to 0.5 eV. The minimum… · DEC 2019

ABC26PH1151 · The molecule that will not absorb in the microwave region, but will absorb in the infra-red region · JUNE 2021

ABC26PH1097 · The uncertainty in the NMR frequency of a compound in liquid state (relaxation time = 1 s) is 0.1 Hz. The uncertainty in the frequency (in… · JUNE 2011

ABC26PH1123 · In an NMR spectrometer containing a 2.5 T magnet, Larmor precession frequency of 1H is 100 MHz. The radiofrequency used in this… · JUNE 2016

ABC26PH0107 · The rotational constant of 14N2 is 2 cm-1. The wave number of incident radiation in a Raman spectrometer is 20487 cm-1. What is the wave… · DEC 2011

ABC26PH1099 · The rotational constant of 14N2 is 2 cm-1. The wave number of incident radiation in a Raman spectrometer is 20487 cm-1. What is the wave… · JUNE 2011

ABC26PH1102 · For the vibrational Raman spectrum of a homonuclear diatomic molecule, the selection rule under harmonic approximation is · JUNE 2012

ABC26PH1129 · Among the following, both microwave and rotational Raman active molecule is · DEC 2016

ABC26PH1133 · The first electronic absorption band maximum of a polar and relatively rigid aromatic molecule appears at 310 nm but its fluorescence… · JUNE 2017

ABC26PH1134 · The molecule that will show Raman spectrum, but not IR spectrum, among the following is · DEC 2017

ABC26PH0104 · The microwave spectrum of a molecule yields three rotational constants. The molecule is · JUNE 2011

ABC26PH1093 · The microwave spectrum of a molecule yields three rotational constants. The molecule is · JUNE 2011

ABC26PH1101 · For a diatomic molecule AB, the energy for the rotational transition from J = 0 to J = 1 state is 3.9 cm-1. The energy for the rotational… · JUNE 2012

ABC26PH1117 · The spectroscopic technique, by which the ground state dissociation energies of diatomic molecules can be estimated, is · JUNE 2015

ABC26PH1119 · The molecule with the smallest rotational constant (in the microwave spectrum) among the following is · DEC 2015