1. What does a strong signal at 3400 cm⁻¹ in an IR spectrum indicate?
(A) Carbonyl
(B) Amine
(C) Alcohol
(D) Alkane
2. Which bonds would be expected to have the highest frequency stretch?
(A) Carbon-bromine single bond
(B) Carbon-carbon double bond
(C) Carbon-carbon triple bond
(D) Carbon-carbon single bond
3. Which bonds would be expected to have the lowest frequency stretch?
(A) C-Cl
(B) C-Br
(C) C-I
(D) C-F
4. In UV-Visible spectroscopy, what effect does an auxochrome have if it shifts absorption to a longer wavelength?
(A) Hyperchromic effect
(B) Bathochromic shift
(C) Hypochromic effect
(D) Hypsochromic shift
5. What is the separation of resonance frequencies of protons in different structural environments from some chosen standard called?
(A) Proton resonance
(B) Chemical exchange
(C) Spin-spin splitting
(D) Chemical shift
6. Which of the following is independent of applied magnetic field in PMR spectroscopy?
(A) Spin-spin splitting
(B) Chemical shift
(C) Both of these
(D) None of these
7. The compound displays a PMR spectrum showing: (i) Triplet for 3 protons, (ii) Quartet for 2 protons. It is likely to be:
(A) CH₃CH₂Br
(B) CH₃CH₂OCH₃
(C) CH₃CH₂OH
(D) CH₃–O–CH
8. Which electronic arrangement is most stable?
(A) Triplet state (T₁)
(B) Singlet state (S1)
(C) Singlet state (S2)
(D) Triplet state (T2)
9. Why is the quantum yield for most photochemical reactions either less or greater than 1?
(A) Primary processes
(B) Termination processes
(C) Secondary processes
(D) None of these
10. Benzophenone reacts with isopropyl alcohol in presence of light to form benzopinacol. This reaction is an example of:
(A) Photodimerization
(B) Photodegradation
(C) Photoisomerization
(D) Photoreduction
11. What is the result of direct irradiation of butadiene alone?
(A) Photodimerization
(B) Photoisomerization
(C) Photoreduction
(D) Photooxidation
12. Photolysis of acetone at room temperature to yield biacetyl and other products is:
(A) Norrish type I reaction
(B) Norrish type II reaction
(C) Paterno–Büchi reaction
(D) None of these
13. What type of reaction is the photodimerization of dibenzyl ketone to form dibenzyl and CO?
(A) Photodimerization
(B) Photoisomerization
(C) Norrish type I reaction
(D) Norrish type II reaction
14. What type of reaction is the photolysis of hexane-2-one to form propene and acetone?
(A) Norrish type I reaction
(B) Paterno–Büchi reaction
(C) Norrish type II reaction
(D) Photoaddition
15. Norrish type II reaction involves which process?
(A) Hydrogen abstraction
(B) Hydride ion abstraction
(C) Proton abstraction
(D) Rearrangement without abstraction
16. What is the name of the reaction where ketones and alkenes form oxetanes under light?
(A) Norrish type I reaction
(B) Paterno–Büchi reaction
(C) Diels-Alder reaction
(D) Norrish type II reaction
17. Photoirradiation of cyclic α, β-unsaturated ketones results in:
(A) Photoreduction
(B) Photodimerization
(C) Photodegradation
(D) Photoisomerization
18. Which compound absorbs at the highest wavelength in the UV region?
(A) 1,4-Pentadiene
(B) 1,3-Pentadiene
(C) Anthracene
(D) Naphthalene
19. Which factor does not shift ultraviolet absorption to a longer wavelength?
(A) Steric hindrance
(B) Resonance
(C) Auxochrome
(D) Conjugation
20. Which type of radiation has the greatest energy?
(A) Ultraviolet
(B) X-ray
(C) Infrared
(D) Visible
21. Which electronic transition requires the maximum energy?
(A) n → σ
(B) π → π
(C) n → π
(D) σ → σ
22. The value of molar extinction coefficient (ε) is related to:
(A) Wavelength of absorption
(B) Probability of transition
(C) Frequency of absorption
(D) All of A, B, and C
23. Bathochromic shift refers to shifting towards:
(A) Lower wave number
(B) Higher wave number
(C) Lower wavelength
(D) None of these
24. Hypsochromic effect in IR spectrum refers to:
(A) Increases the intensity of absorption
(B) Lowers the intensity of absorption
(C) Lowers the wavelength of absorption
(D) Increases the frequency of absorption
25. What is a chemical reaction that occurs as a consequence of light absorption called?
(A) Fluorescence
(B) Photo reduction
(C) Chemiluminescence
(D) Photochemical reaction
26. What process involves the dissociation of molecules to form free radicals upon light absorption?
(A) Secondary process
(B) Primary process
(C) Fluorescence
(D) Phosphorescence
27. Magnetic properties are not observed in nuclei with:
(A) Odd mass number and odd atomic number
(B) Even mass number and even atomic number
(C) Odd mass number and even atomic number
(D) Even mass number and odd atomic number
28. Which nucleus is insensitive to nuclear magnetic resonance?
(A) 16O
(B) 2H
(C) 19F
(D) 1H
29. What is the spin quantum number (S) for a proton?
(A) 0
(B) 4
(C) 1/2
(D) 3/2
30. In vibrational-rotational bands, the absorption frequency or wavelength depends on:
(A) Relative masses of the atoms
(B) The force constant of the bonds
(C) Geometry of the atoms
(D) All
31. What is the relation between wave number (v) and wavelength, where c is the speed of light?
(A) v = c/λ
(B) v = 1/λ²
(C) v = 1/λ
Answer: (C) v = 1/λ
32. What is the range of vacuum ultraviolet region?
(A) 100–200 nm
(B) 200–400 nm
(C) 400–800 nm
(D) 100–400 nm
33. Absorption of ultraviolet radiation by a molecule causes which of the following?
(A) Rotational excitation
(B) Vibrational excitation
(C) Electronic excitation
(D) All of A, B, and C
34. How many orientations can a spinning proton take in an applied magnetic field?
(A) 2
(B) 1
(C) 4
(D) 6
35. Resonance occurs when the frequency of electromagnetic radiation in a constant magnetic field equals the _______ of spinning nuclei.
(A) Spinning frequency
(B) Spin quantum number
(C) Precessional frequency
(D) All of A, B, and C
36. ons and duplet for 1 proton
(D) Quartet for 3 protons and duplet for 1 proton
Answer: (D) Quartet for 3 protons and duplet for 1 proton
37. Mass spectrometry studies the spectrum of _____.
(A) Positively charged ions
(B) Negatively charged ions
(C) Neutral radicals
(D) All of A, B, and C
38. Which is a forbidden transition?
(A) n-π*
(B) n-π*
(C) π-π*
(D) None of these
39. The parent molecular ion spectrometry is helpful and used to determine:
(A) Molecular weight
(B) Bond energy
(C) Functional group
(D) All of A, B, and C
40. Mass spectrum of an alcohol gives a strong peak at m/e 31. The alcohol is likely to be a:
(A) Tertiary alcohol
(B) Secondary alcohol
(C) Primary alcohol
(D) Any one of these
41. The parent molecular ion [C₆H₅COCH₃]⁺ is likely to fragment as:
(A) CH₃ + C₆H₅ – C⁺ = O
(B) C₆H₅ + CH₃ – C⁺ = O
(C) CH₃ + C₆H₅ – C⁻ = O
(D) C₆H₅ + CH₃ – C⁻ = O
42. The number of rings and double bonds in a positive ion having the formula C₇H₇ is:
(A) One ring + 2 double bonds
(B) Two rings + 1 double bond
(C) One ring + 3 double bonds
(D) Two rings + 3 double bonds
43. Which best describes the PMR spectrum of C₆H₅CHO?
(A) Two singlet peaks
(B) One duplet peak + one hexatet peaks
(C) One duplet + one singlet peaks
(D) Two duplet peaks
44. Absorption of radiation by olefins in proper ultraviolet region results in the electronic transition of the type:
(A) σ → σ*
(B) σ → π*
(C) π → π*
(D) n → π*
45. Excited state formed initially by absorption of radiation by a molecule is usually:
(A) Singlet state
(B) Triplet state
(C) Transition state
(D) None of these
46. The absorption of light by molecules undergoing photochemical reactions usually results in:
(A) Phosphorescence
(B) Fluorescence
(C) Homolytic fission
(D) Heterolytic fission
47. Which electronic transition cannot be studied by quartz ultraviolet spectroscopy?
(A) n-σ*
(B) π-π*
(C) σ-σ*
(D) n-n*
48. Which is helpful and used as a source of visible radiation?
(A) Hydrogen discharge lamp
(B) Tungsten filament lamp
(C) Deuterium discharge lamp
(D) All of A, B, and C
49. Which solvents cannot be helpful and used for the UV/VIS spectral study of aldehydes?
(A) n-Hexane
(B) Cyclohexane
(C) Acetonitrile
(D) Ethanol
50. Which mode of vibration is in-plane bending?
(A) Rocking
(B) Wagging
(C) Twisting
(D) None of these
51. What is the vibration degree of freedom of molecule of methane?
(A) Fifteen
(B) Nine
(C) Five
(D) None of these
52. Which bonds show stretching absorption in the 3700–2500 cm⁻¹ region?
(A) C–C
(B) C–N
(C) C–O
(D) None of these
53. Which bonds do not show stretching absorption in the 3700–2500 cm⁻¹ region?
(A) C–H
(B) C–C
(C) O–H
(D) N–H
54. Which is not helpful and used as a source of IR radiation?
(A) Nernst filament
(B) Globar
(C) Tungsten filament
(D) None of these
55. Which material is helpful and used for making the circular flat plates to hold the sample for IR study?
(A) Rock salt
(B) Quartz
(C) Glass
(D) All of A, B, and C
56. Which electronic transition occurs when methanol is exposed to ultraviolet radiation?
(A) n-σ*
(B) π-π*
(C) n-n*
(D) None of these
57. In which form can a solid sample be studied by IR spectroscopy?
(A) As a solution
(B) As a KBr disc
(C) As a mull
(D) Any of these
58. Which can be helpful and used to prepare the mull of a solid sample for its IR study?
(A) Toluene
(B) Benzene
(C) Nujol
(D) Water
59. Which is commonly helpful and used as a solvent for IR study?
(A) Methanol
(B) Ethanol
(C) Water
(D) None of these
60. Which is not commonly helpful and used as a solvent for IR study?
(A) Carbon disulfide
(B) Chloroform
(C) Carbon tetrachloride
(D) Ethanol
61. Where does the C-H stretching absorption of an olefin appear in an infrared spectrum?
(A) At 3000 cm⁻¹
(B) Below 3000 cm⁻¹
(C) Above 4020 cm⁻¹
(D) In the 1650-1600 cm⁻¹
62. Which compounds do not absorb light in the UV/visible spectrum?
(A) Aspirin
(B) Benzene
(C) Phenol
(D) All of A, B, and C
63. In infrared spectroscopy, which frequency range is called the fingerprint region?
(A) 1400-1200 cm⁻¹
(B) 600-250 cm⁻¹
(C) 900-600 cm⁻¹
(D) 400-900 cm⁻¹
64. In UV-visible spectrophotometry, what does absorbance measure?
(A) The fraction of light of a particular wavelength absorbed by a sample
(B) The fraction of light of a particular wavelength transmitted by a sample
(C) The total amount of light energy absorbed by a sample
(D) The intensity of light that emerges from a sample
65. The main advantage of fluorescence over UV-Vis spectroscopy is:
(A) Its compatibility with separation techniques
(B) Its sensitivity
(C) That emission spectra give fairly sharp peaks
(D) Its compatibility with most analytes
66. Infrared spectroscopy gives us important information about:
(A) Molecular weight
(B) Melting point
(C) Functional groups
(D) Conjugation
67. In UV-visible spectroscopy, auxochromes shift the position of absorption to shorter wavelengths called:
(A) Hypsochromic shift
(B) Hyperchromic effect
(C) Bathochromic shift
(D) Hypochromic effect
68. Homodienic components ______ than heterodienic systems:
(A) Equally shift the position of absorption to longer wavelength
(B) Shift the position of absorption more to the longer wavelength
(C) Shift the position of absorption less to the longer wavelength
(D) None of these
69. According to Woodward-Fieser rules, an increment of ______ is added to parent value for double bond extended conjugation:
(A) 214
(B) 30
(C) 15
(D) 5
70. The IR spectrum of amines shows N-H stretching at:
(A) 3050-3550 cm⁻¹
(B) 1050-3550 cm⁻¹
(C) 4050-5550 cm⁻¹
(D) 2050-3550 cm⁻¹
71. The IR spectrum of carboxylic acid shows O-H stretching at:
(A) 1250-3550 cm⁻¹
(B) 1050-3550 cm⁻¹
(C) 2500-3550 cm⁻¹
(D) 4050-5550 cm⁻¹
72. The IR spectrum of carboxylic acid shows >C=O stretching at:
(A) 2050-3550 cm⁻¹
(B) 1700-1750 cm⁻¹
(C) 3000-5000 cm⁻¹
(D) 1050-3550 cm⁻¹
73. PMR spectra of ethyl acetate is essentially:
(A) Three singlet peaks
(B) One triplet, one doublet and one singlet peaks
(C) Two triplets and one singlet peaks
(D) One quartet, one triplet and one singlet peaks
74. In H-NMR, circulating π-electrons of benzene add to:
(A) Deshielding effect
(B) Shielding effect
(C) Both of these
(D) None of these
75. In H-NMR, high acetylene adds to electron density in:
(A) Deshielding effect
(B) Shielding effect
(C) Both of these
(D) None of these
76. In evaluating chemical shift value, the nucleus that is deshielded will have:
(A) May have lower or higher value
(B) Lower chemical shift value
(C) Higher chemical shift value
(D) None of these
77. Woodward-Fieser rules are applied for:
(A) α, β-Unsaturated carbonyl compounds
(B) Cyclic Hydrocarbons
(C) Allenes
(D) Non conjugated polymer
78. Homoannular diene λmax value according to Woodward-Fieser rules:
(A) 214
(B) 234
(C) 217
(D) None of them
79. Which is true regarding Auxochrome?
(A) Ph-
(B) OH, NH₂, -OR
(C) Ethene & Ethyne
(D) All of A, B, and C
80. Which part of spectrophotometer is helpful and used to convert electromagnetic radiation into monochromatic radiation?
(A) Deuterium lamp
(B) Monochromator
(C) Detector
(D) None of A, B, and C
81. Scissoring, rocking, wagging are the vibration:
(A) Stretching vibration
(B) Symmetrical vibration
(C) Bending vibration
(D) Both a & b
82. Aromatics have diagnostic peaks in the ______ region of IR spectra:
(A) 1200-1000 cm⁻¹
(B) 900-700 cm⁻¹
(C) 1700-1500 cm⁻¹
(D) None of A, B, and C
83. Carbonyl displays absorption peaks in IR spectra at:
(A) 1900-1600 cm⁻¹
(B) 1200-1000 cm⁻¹
(C) Both a & b
(D) 2300-2100 cm⁻¹
84. Monochromator helpful and used in UV spectroscopy:
(A) Laser
(B) Glass prism
(C) Grating
(D) Glass print
85. The IR spectrum of aldehydes and ketones show strong >C=O stretching at:
(A) 2050-3550 cm⁻¹
(B) 2050-4000 cm⁻¹
(C) 4050-5550 cm⁻¹
(D) 1700-1750 cm⁻¹
86. The IR spectrum of phenol shows O-H stretching at:
(A) 2050-3550 cm⁻¹
(B) 1050-3550 cm⁻¹
(C) 4050-5550 cm⁻¹
(D) 3200-3550 cm⁻¹
87. The IR spectrum of alcohol shows O-H stretching at:
(A) 3580-3650 cm⁻¹
(B) 1050-3550 cm⁻¹
(C) 5000-5550 cm⁻¹
(D) 2050-3550 cm⁻¹
88. Atomic spectra is an example of:
(A) Continuous spectra
(B) Line spectra
(C) Band spectra
(D) Both A and B
89. Modern method for separation of isotopes:
(A) X-ray
(B) Chromatography
(C) Ionization
(D) Laser separation
90. In new spectrometers each ion hits a
(A) Ionizer
(B) Detector
(C) Collector
(D) Graph
91. Force constant gives an idea about the
(A) Dipole moment of bond
(B) Reduced mass
(C) Strength of bond
(D) Wave number of absorptions
92. For a linear molecule the number of vibrational degrees of freedom are (where n = number of atoms)
(A) 3n-5
(B) 3n-6
(C) 3n
(D) Relies on type of atoms
93. Which pair of compounds cannot be distinguished on the basis of UV spectra?
(A) Ethyl formate and methyl acetate
(B) Benzene and naphthalene
(C) 1,3-Pentadiene and 1,4-Pentadiene
(D) Acetaldehyde and benzaldehyde
94. Which is not an auxochrome group?
(A) NHR-
(B) B.-NH2
(C) -NR
(D) -NO2
95. Mass spectrometer to determine isotopes in solid state is
(A) Bohr’s
(B) Dempster’s
(C) Aston’s
(D) Alison’s
96. In accelerating chamber of spectrometer potential difference is
(A) 600-7000
(B) 500-2000
(C) 300-8000
(D) 700-9000
97. Far infrared region of the electromagnetic radiation usually lies between
(A) 1-20 μm
(B) 100-400 μm
(C) 50-1000 μm
(D) 50-200 μm
98. Microwave region of electromagnetic spectrum usually lies between
(A) 500-1000 cm
(B) 50-100 cm
(C) 0.1-100 cm
(D) 60-150 cm
99. Radio waves region of the spectrum usually lies between
(A) 100-500 m
(B) 300-700 m
(C) 1-1000 m
(D) 1-100 m
100. For a particular molecular species, this of the following terms is a function of concentration
(A) Transmission
(B) Percent transmission
(C) Absorbance
(D) All