PPSC Chemistry Lecturer Preparation (Test # 17)- Malik Xufyan 03137355727

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PPSC CHEMISTRY CLASS
Test Session
Chapter: Spectroscopy
Topic: IR Spectroscopy
Test No. 17
For more WhatsApp # 0313-7355727
1. Mid-IR region mainly consists of
a) 4000 – 100 cm -1
b) 14000 – 4000 cm -1
c) 4000 – 400 cm-1
d) 400 – 100 cm -1
2. Over tones are mainly observed in
a) Near IR
b) Mid IR
c) Far IR
d) Not in IR region
3. Which of the following region has more wavelength
a) UV
b) Far UV
c) Near IR
d) Far IR
4. The IR region most widely used for qualitative analysis is
a) Near IR
b) Mid IR
c) Far IR
d) All of the above
5. The correct order of different types of energies is __________
a) Eel >> Evib >> Erot >> E tr
b) Eel >> Erot >> Evib >> E tr
c) Eel >> Evib >> Etr >> E rot
d) Etr >> Evib >> Erot >> E el
6. Given below is the stretching vibration of a diatomic molecule. The reduced mass of
the two atoms involved in this stretching vibration will be
a) μ=(m 1 + m 2)/m 1m 2
b) μ=m1 m2/(m1 + m2)
c) μ=(m 1 + m 2)/2
d) μ=(m 1 + m 2)/2m 1m 2
7. The vibrational frequency of stretching vibration of the diatomic molecule will be
a) ν/2π=√(μ/k)
b) ν/2π=√(k/μ)
c) ν=1/2π √(μ/k)

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d) ν=1/2π √(k /μ)
8. Which of the following absorb IR radiation
a) Homonuclear diatomic molecule
b) Heteronuclear diatomic molecule
c) Both A and B
d) Diatomic molecules will not absorb IR
9. In FTIR, initially spectra is recorded as
a) Volts vs time
b) % Transmittance vs concentration
c) Absorbance vs Concentration
d) Absorbance vs time
10. The possible number of vibrational bands for CO 2 is
a) 2
b) 3
c) 4
d) 5
11. Non-dispersive IR spectrophotometer will not have
a) Source
b) Monochromator
c) Cell
d) Detector
12. Which of the following transitions mainly occur in IR?
a) Electronic transitions only
b) Rotational and vibrational transitions
c) Rotational transitions only
d) All the electronic, rotational, vibrational transitions
13. How many vibrational modes are possible for HCl
a) 0
b) 1
c) 2
d) 3
14. How many vibrational modes are possible for CCl 4
a) 0
b) 6
c) 10
d) 9
15. Which of the following vibrational mode of CO 2 is IR active
a) Symmetric stretching
b) Asymmetric stretching
c) Both A and B
d) None
16. All of the following are the degrees of freedom for a molecule at any instance, except
a) Electronic
b) Vibrational

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c) Rotational
d) Translational
17. How many vibrational modes are possible for acetylene?
a) 2
b) 6
c) 7
d) 8
18. The intensity of an absorption band is always proportional to which of the following
factor?
a) Atomic population
b) Molecular population of the initial state
c) Molecular population of the final state
d) Temperature
19. For HCI = 1.63 x 10-27 kg, the observed frequency = 2890 or v = 8.67 x 1013 Hz. What
is the force constant K?
a) 4.83 m dyn Å-1
b) 8.43 dynes cm-1
c) 483 μm-1
d) 4.83 dyn Å-1
20. The vibrations, without a centre of symmetry are active in which of the following
region?
a) Infrared but inactive in Raman
b) Raman but inactive in IR
c) Raman and IR
d) Inactive in both Raman and IR
21. What is the order of decreasing vibrational frequency for C — Cl, C — Br, C — C,
C — O and C — H?
a) C-H, C-C, C-O, C- Cl, C-Br
b) C- Cl, C-Br, C-C, C -H, C-O
c) C-O, C-H, C-Br, C- Cl, C-C
d) C-Br, C- Cl, C-C, C-O, C-H
22. What is the correct increasing order of stretching frequencies for C ≡ C, C = C and
C —C?
a) C — C > C = C > C ≡ C
b) C ≡ C > C = C > C — C
c) C — C > C = C < C ≡ C
d) C ≡ C < C — C > C = C
23. The IR band for C≡ N group is observed in the range of __________
a) 3000 – 2800 cm-1
b) 3400 – 3300 cm-1
c) 2260 – 2200 cm-1
d) 1750 – 1650 cm-1
24. The IR band for -NH2 group is observed in the range of __________
a) 3000 – 2800 cm-1

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b) 3400 – 3300 cm-1
c) 2200 – 2100 cm-1
d) 1750 – 1650 cm-1
25. In IR spectroscopy, the wavenumber for carbonyl group is observed in the range of
a) 3500-3300 cm-1
b) 2200-2100 cm-1
c) 1740-1650 cm-1
d) 3000-2800 cm-1
26. The region of electromagnetic spectrum for nuclear magnetic resonance is
__________
a) Microwave
b) Radio frequency
c) Infrared
d) UV-rays
27. The frequency of a transition is 5.4 × 1015 Hz. What is the corresponding wave-
length?
a) 180 000 cm–1
b) 5.6 × 10–6 m
c) 560 nm
d) 5.6 × 10–8 m
28. The frequency of a transition is 3.1 × 1010 Hz. What is the energy of this transition?
a) 2.0 × 10–23
kJ
b) 2.0 × 10–23
J
c) 2.1 × 10–44
kJ
d) 2.1 × 10–44
J
29. Which of the following statements is correct?
a) Infrared radiation has a shorter wavelength than visible light.
b) Microwave radiation possesses more energy than infrared radiation.
c) Ultraviolet radiation has a longer wavelength than infrared radiation.
d) Infrared radiation has a lower wavenumber than visible light.
30. A shift to lower wavenumber for an absorption in a spectrum corresponds to:
a) a shift to lower wavelength.
b) a shift to higher energy.
c) a loss of intensity.
d) a shift to lower frequency.