1. Illustrate what is an electromagnetic radiation. Define various parameters associated with it.  

2. What are term symbols? Derive the term symbols for the p state of the hydrogen atom.  

3. (a) Give the shapes of the following molecules:  

(i) HgCl2

(ii) SnCl2

(iii) ClF3

(iv) XeF4

(v) PCl5

(vi) PF3

(b) Show that a two fold axis of symmetry is present in water molecule.  

4. Illustrate the symmetry elements present in benzene molecule. What is its point group? 

5. Discuss the origin of various spectral lines the rotational spectrum of a diatomic molecule. Draw a suitable diagram also. 

6. Draw and explain the infrared spectral bands for HCl molecule. 

7. Explain the following terms:  

(i) Vibrational term value

(ii) Anharmonicity

8. (a) How many normal modes of vibration are possible for a (5)

(i) linear molecule, and

(ii) Non-linear molecule? b) Draw the stretching and bending modes for CH2 group. 

9. Briefly explain the bands which are observed in the 4000-2500 cm1 region of IR spectra for various organic molecules.

10. Discuss important aspects of polarised Raman spectrum. 

11. Explain Born-Oppenheimer approximation with the help of a suitable diagram. 

12. Write the ground state electronic configuration of ethylenic chromophore. Discuss the possible electronic transitions for this chromophore using a suitable diagram. 

13. Give reason for the following: 

(i) Mercury iodide is red in colour.

(ii) An aqueous solution of NiSO4 is green in colour which turns deep blue on addition of ethylenediamine.

14. Discuss the predissociation using a suitable diagram.  

15. (i) What is the role of littron mirror in IR spectrometre?

(ii) Why can glass cell not be used for IR spectroscopy?

(iii)What is the significance of monochromators?

(iv) What are the sources of radiation in Raman spectrometre?

(v) What is the significance of laser beam in Raman spectroscopy?

16. What is nuclear Zeeman effect? Why is this observed? Explain.  

17. What is relaxation phenomenon? Explain its importance and different types.  

18. How is an esr spectrum recorded? Explain. Also draw the block diagram of the esr spectrometer. 

19. Explain simple cleavage for alkanes and the fragments obtained in the mass spectrum by taking a suitable example. 

20. Explain the spectral data expected for 2-butanone.