LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – APRIL 2012

CH 5508 – FUNDAMENTALS OF SPECTROSCOPY

 

 

 

Date : 03-05-2012              Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

 

Answer ALL questions:                                                                                        (10 x 2 = 20 Marks)                                                         

 

1. Arrange the following spectral regions in the increasing order their frequencies (a) UV   (b) IR

(c) X – ray (d) Microwave (e) cosmic rays.

2. Distinguish between absorption and emission spectrum.
3. Write the mathematical expression for Beer – Lamberts law.
4. What is the wavelength of UV, IR regions in the electromagnetic spectrum?
5. What is finger print region?
6. How are CH₃CH₂COCH₃ and CH₃CH₂CH₂OH distinguished using IR spectroscopy?
7. What is coupling constant?
8. Why TMS is used as a reference in NMR spectroscopy?
9. Define base peak.
10. Name the parts of a mass spectrometer.

 

PART – B

 

Answer any EIGHT questions:                                                                                       (8 x 5=40Marks)

 

11. Describe the factors that determine the intensity of spectral lines.
12. Discuss various types of electronic transition with a suitable diagram.
13. State and explain Frank – Condon principle.
14. Discuss the instrumentation of photocolorimeter.
15. Explain Rayleigh and Raman effects.
16. State Mutual exclusion principle and discuss the geometry of CO₂ and N₂O.
17. Write any 5 differences between IR and Raman spectrum.
18. Discuss the instrumentation of NMR spectroscopy.
19. Explain spin – spin coupling.
20. How many signals appear in the NMR spectrum of a) toluene b) propyl alcohol   c) acetone
21.  d) ethyl alcohol    e) acetaldehyde?
22. Explain nitrogen rule in mass spectrometry.
23. Write notes on metastable peak.

PART – C

Answer any FOUR questions:                                                                                        (4×10=40 Marks)

 

23. Explain the following terms with suitable examples.
24. a) chromophore   b) Bathochromic shift     c) auxochrome.                                                     (10)
25. Discuss the principle, instrumentation and application of flame Photometry.      (10)
26. a) Discuss stretching and bending vibrations.                         (5+5)
27. b) Discuss the selection rules of Raman spectrum.
28. a) Explain the sampling techniques in IR spectroscopy.    (5+5)
29. b) Distinguish the following using IR spectra:
30. i) CH₃CH₂CHO and CH₃COCH₃
31.    ii) CH₃CONH₂ and CH₃NH₂

iii) C₂H₅OH and C₂H₅Cl.

27. a) Explain McLafferty rearrangement.    (5+5)
28. b) Write notes on shielding and deshielding effects.
29. a) Discuss the basic principles of mass spectrum.    (5+5)
30. b) Determine the structure of the compound whose m/e values in the mass spectrum

are 100, 85, 71, 57, 43(base) 41, 29 and 27.

 

 

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