LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – CHEMISTRY
FIFTH SEMESTER – NOVEMBER 2010
CH 5508 – FUNDAMENTALS OF SPECTRASCOPY
Date : 09-11-10 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART – A
Answer ALL the Questions (10 x 2 = 20 marks)
- Which electromagnetic radiation has wave length 1 m? Give the frequency of that
electromagnetic radiation.
- Explain signal-noise ratio.
- State Beer-Lambert’s Law.
- What are chromophores and auxochromes?
- Why water cannot be used as a solvent in IR spectral analysis?
- How will you distinguish intramolecular hydrogen bonding from intermolecular hydrogen
bonding by IR spectroscopy?
- Define coupling constant.
- Why is KMnO4(ag) coloured?
- What is the difference between base peak and molecular ion peak?
- If the m/e value of the molecular ion [M] is 173 and there is an [M+2] peak with equal
relative abundance, what are your inferences?
PART – B
Answer any EIGHT Questions (8 x 5 = 40 marks)
- Distinguish between the following:
- Absorption spectra-emission spectra.
- Electronic energy levels-rotational energy levels.
- Write the principle of ASS and explain its instrumentation.
- Write the Boltzmann distribution formula and explain.
- ‘Isotopic peaks have a rich source of information’ – Justify.
- Enlist the factors that affect chemical shift values.
- Explain the different types of electronic transitions.
- Describe the various IR bands for ethyl benzoate.
- Using NMR spectroscopy, how will you differentiate between
- 1-propanol and 2-propanol.
- Acetone and acetaldehyde.
- Discuss mutual exclusion principle.
- Write a note on sample handling in IR spectroscopy.
- Can you distinguish CH3 CH2 OCH3 from (CH3)2 CHOH by PMR Spectroscopy?
- Explain the fragmentation pattern of n-butanol.
PART – C
Answer any FOUR Questions (4 x 10 = 40 marks)
- Draw the block diagram of double beam IR spectrometer and explain its components.
- List out the difference between (i) IR and Raman spectroscopy (ii) Stoke’s and antistoke’s
lines.
- a) What are the merits of TMS?
- b) Discuss the basic instrumentation in NMR.
- a) How will you determine the structure of a compound whose m/e value are 86 (molecular
ion), 57 (base peak), 29?
- b) What are the factors that affect absorption maximum and intensity in UV-visible
spectroscopy?
- Discuss the principle and applications of flame photometry.
- Explain a) MCLafferty rearrangement b) high resolution NMR Spectrum of ethanol.
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