WD 32

     LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – April 2009

CH 2815/CH 2809 – CHEMISTRY OF MAIN GROUP ELEMENTS

 

 

 

Date & Time: 22/04/2009 / 1:00 – 4:00         Dept. No.                                                           Max. : 100 Marks

 

 

PART – A

 

Answer ALL the questions                                                                                     (10 x 2 = 20)

 

1. What are electron deficient compounds? Give an example.
2. Why are oxides of non-metals acidic?
3. What are calixeranes?
4. Give the structure and laboratory use of iodinepentoxide.
5. How is inorganic benzene prepared?
6. What is the reaction of an alcohol with disilaethenes?
7. What are pyrazoboles? Give two examples.
8. Mention any two applications of sulphides of phosphorus.
9. How is C₂B₁₀H₁₂, carboranes prepared? Give the structure
10. Which of the following compounds possesses high Lewis basicity.
11. i) Si(CH₃)₄  ii) As(CH₃)₄. Give reasons.

 

PART – B

Answer any EIGHT  questions                                                                               (8 x 5 = 40)

 

11. Compare the catenation properties of carbon and silicon, assigning reasons.
12. Explain the biological significance of magnesium.
13. Compare structures and properties of allotropes of carbon.
14. Give preparation, properties and structures of any two chlorine oxides.
15. Give preparation of oxides of xenon. Why are they not obtained by direct combination?
16. Write notes on synthetic importance of boranes.
17. Explain the principle and the role of brominating mixture (bromate-bromide) in volumetric analysis
18. Explain the different methods (any four) of preparation of lithium organometallic compounds.
19. Explain the classification of silicates with examples.
20. Discuss the preparation, properties and uses of silanes.
21. Discuss the synthetic applications of any two sulphides of phosphorus and discuss their structures.
22. What are macrocyclic ligands ? Give the molecular structure of any two nitrogen containing macrocyclic ligands and explain their significances.

 

PART – C

 

Answer any FOUR questions                                                                                  (4 x 10 = 40)

 

23. Discuss nature of bonds present in E-H and E-X and their reactivity.

(E= carbon and silicon; X= halogen)

24. Discuss the preparation, structure and chemistry of various halogen compounds of nitrogen.
25. Write an essay on organometallic compounds with reference to their stabilities and synthetic significance.
26. Explain Why borazine is considered as inorganic benzene where as phosphazenes are not considered as inorganic benzene?
27. Explain the structure and bonding in diborane.
28. Discuss the types of bonding by giving styx number and predict the geometry of the following compounds by PSEPT theory
29. i) B₅H₁₁  ii)B₅H₉           iii)B₄H₁₀          iv) B₆H₁₀

 

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