LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – APRIL 2012

CH 5505 – ORGANIC FUNCTIONAL GROUPS – II

 

 

 

Date : 25-04-2012              Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

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

 

1. Why Nitrobenzene is often used as solvent in Friedel Crafts reaction.
2. How will you prepare nitroethane by vapourisation method?
3. Assign R and S configuration to the following:

   

                                                

4. What are enantiomers? Give two properties of enantiomers.
5. Explain Walden inversion using S_N2 reaction.
6. Explain keto-enol tautomerism exhibited by acetoacetic ester.
7. What is Cope rearrangement?
8. Give the products of the following reaction:

      

9. What is isoprene rule? Indicate the isoprene units in the structure of α-pinene.
10. Write the structure of Conine.

         

PART – B

Answer any EIGHT questions:                                                                 (8 x5 = 40)

 

11. Give the products obtained when Nitrobenzene is reduced in
12. a) Strongly acidic solution
13.  b) Strongly alkaline solution.
14. Using Hinsberg test,how will you distinguish between

       N-methylaniline and N,N’ dimethyl aniline.

13. Explain why pyridine is more basic than pyrrole.
14. i) What is asymmetric synthesis?
15. ii) How will you prepare (-) lactic acid from pyruvic acid?
16. Discuss the optical isomerism exhibited by biphenyl compounds.
17. How will you synthesize adipic acid from ethyl acetoacetate?
18. How will you synthesize propionic acid from acetic acid using Arndt – Eistert

      reaction.

18. Describe Hoffmann rearrangement. Discuss its mechanism.
19. Describe Fries rearrangement and give its mechanism.
20. Complete the following reactions.

 

       

21. How will you synthesize nicotine from nicotinonitrile?
22. What are the products obtained when Citral is subjected to oxidation with

       alkaline KMnO₄  followed by chromic acid?

 

PART – C

 

Answer any FOUR questions:                                                                              (4 x 10 =40)

 

23. i. How is Nitrobenzene prepared from benzene? Give its mechanism.
24. How will you prepare o-dinitrobenzene and p-dinitrobenzene from Aniline?

 

24. i. What is diazotisation? How is benzene diazonium chloride prepared in the

         laboratory?

1. Explain Gattermann and Sandmeyer reactions using suitable examples.

 

25. i. Discuss Claisen rearrangement with a specific example . Give its mechanism.
26. How will you prove that in Claisen rearrangement ,o-isomerisation takes place

         with inversion of position?

 

26. i. Describe the various methods for the resolution of racemic mixtures.
27.    Explain the phenomenon of racemisation taking a suitable example.

 

27. i. How is Quinoline prepared by Skraup’s synthesis?
28. Electrophilic substitution in pyrrole takes place at 2- position whereas in

          pyridine at 3- position. Why?

 

28. i. What are Alkaloids? How are they extracted from plants?
29. How are Terpenes classified?

       iii. What are the structural formula and uses of

1. Menthol b. α-Pinene  c. Camphor. 

 

 

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