LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

   B.Sc. DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – NOVEMBER 2010

CH 5505 – ORGANIC FUNCTIONAL GROUPS – II

 

 

 

Date : 29-10-10                     Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART – A

 

Answer ALL questions.                                                                                             (10 x 2 = 20 marks)

 

1. Explain why nitration of nitrobenzene is more difficult than that of benzene.
2. Account for the fact that Nitromethane is acidic.
3. Give the IUPAC name of
4. CH₃-NH-C₂H₅  ii.CH₃-N(CH₃) –CH₃.
5. What are diastereomers?Explain with an example.
6. Explain Walden inversion using S_N2 reaction.
7. Show how will you prepare 3-methylpentanoic acid from diethyl malonate.
8. What is Cope rearrangement.
9. Give the products of the following reaction

    

    ii.

       

 

9. What is isoprene rule?
10. Write the structure of piperic acid.

 

PART – B

Answer any EIGHT questions                                                                                    (8 x 5 = 40 marks)

 

11. Give the products obtained when Nitrobenzene is reduced electrolytically in
12. Strongly acidic solution.
13.   Strongly alkaline solution.
14. Arrange the following in decreasing order of basicity giving suitable reasons.

       Aniline, p-Nitroaniline , m-Nitroaniline and  Diphenylamine.

13. What is coupling reaction?Give the products obtained when benzene diazonium

      chloride reacts with i. phenol  ii. N, N-dimethylaniline.

14. i. What is asymmetric synthesis?
15. How will you prepare (-) lactic acid from pyruvic acid?
16. Discuss the optical isomerism exhibited by biphenyl compounds.
17. How will you synthesize n-butyric acid from ethyl acetoacetate?
18. How will you synthesize propionic acid from acetic acid using Arndt – Eistert

      reaction.

18. Describe Pinacole –Pinacolone rearrangement.Discuss its mechanism.
19. Describe Curtius rearrangement and give its mechanism.
20. Give the mechanism and orientation of electrophilic substitution in pyridine.
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 marks)

 

23. i. How is Nitrobenzene prepared from benzene? Give its mechanism.             (5)
24. How will you prepare o-Nitroaniline and p-Nitroaniline from Aniline      .                                   (5)

 

24. i. How is benzene diazonium chloride prepared in the laboratory. (4)
25. Explain Gattermann and Sandmeyer reactions using suitable examples.                         (4)

      iii. How will you prepare Phenol from benzene diazonium chloride.                                                 (2)

 

25.i. Discuss Claisen  rearrangement with a specific example . Give its mechanism.                  (5)

1. How will you prove that in Claisen rearrangement ,o-isomerisation takes place

         with inversion of position.                                                                                                                   (5)

 

26. i. Describe any one method for the resolution of racemic mixtures.             (4)
27. Explain by giving an example the phenomenon of racemisation.                                       (3)

• Assign R and S configuration to the following Fischer projection.                  (3)

 

1.                                                         iii.

                        

 

27. i. How is Quinoline prepared by Friedlander synthesis using o-Amino benzaldehyde. (5)

      ii.Complete the following reactions.                                                                                                       (2)

        a.

           

 

        b.

           

       

      iii.Explain why pyridine is more basic than pyrrole?                                                                          (3)

28.i.What are Alkaloids? How are they extracted from plants.                                                                (5)

     ii.What are the structural formula and uses of

1. Menthol b. α-Pinene  c. Camphor.                                                                                              (5)

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

   B.Sc. DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – NOVEMBER 2010

CH 3502 – ORGANIC FUNCTIONAL GROUPS – I

 

 

 

Date : 30-10-10                     Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART – A

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

 

1. Arrange the following compounds in increasing order of reactivity towards S_N2

          reaction. Give reasons.

          t-butyl chloride, n-propyl chloride.

 

2. How is benzyl chloride prepared from benzaldehyde.

 

3. Why does phenol have higher boiling point than toluene.

 

4. Complete the reaction

 

           

 

5. Give the IUPAC name of the following compounds

 

 

6. How will you prepare phenyl methyl ether from phenol using Williamson’s synthesis?

 

7. What happens when calcium acetate is heated? Give its equation.

 

8. What is Norrish type –I reaction.

 

9. What is trans esterification.

 

10. Arrange the following in terms of increasing acid strength and give reasons.

           Propionic acid , 2chloropropionic acid , 2 fluoropropionic acid.

 

PART – B

Answer any EIGHT questions                                                                  (8 x 5 = 40)

11. Give a mechanism for the reaction of tert.butyl bromide with aqueous NaOH to

  form tert.butyl alcohol.

12. Explain Saytzeff rule and Hofmann rule with an example.
13. How is phenol prepared from Cumene.
14.    Although both phenol and alcohols contain hydroxyl group, Phenol is acidic    

            whereas aliphatic alcohols are not acidic – Explain.

15. How will you prepare primary,secondary and teritiary alcohols from Grignard

            reagent.

16. How is ethyl methyl ether prepared by Williamson’s synthesis.What  type of

            mechanism is followed.

17. Write a short note on cleavage of ethers by acids.
18. Discuss the mechanism of Cannizaro reaction.
19. Explain crossed aldol condensation with an example.
20. What is Wittig reaction ? Explain its mechanism.
21. Discuss the geometric isomerism of unsaturated dicarboxylic acids.
22. Explain the mechanism of alkaline hydrolysis of esters.

 

                                                        PART – C

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

 

23. a) Explain the fact that allyl chloride undergoes substitution reaction by SN1 

                mechanism whereas n-propyl chloride reacts by SN2 mechanism.

1.   b) Discuss the Mechanism of E1 and E2 reactions of alkyl halides.

                     

24. a) Give the mechanism of Reimer Tiemann reaction and Kolbe’s reaction.
25. b) How is phenolphthalein prepared from phenol?

 

25. i. How is acetic acid converted to ethyl acetoacetate.
26.          How would you prepare the following compounds from acrylic acid.
27. Propionic acid.
28. Glyceric acid.
29. 2- bromo propionic acid.

 

26. a) How is ethylene oxide prepared?
27.     b) How does diethyl ether react with

                 i.O₂/long contact    ii.PCl₅

1.  c) How does ethylene oxide react with the following reagents:
2.        H₂O/H⁺   ii. HBr   iii.CH₃CH₂OH  iv.NH₃.

 

27.   i. How will you prepare the following compounds
28.               a) 2-propanol from CH₃CHO
29.             b) Lactic acid from CH₃COCH₃
30.           Discuss the mechanism of Reformatsky reaction.         

 

28. a) Write notes on Clemmensen reduction and Wolff-Kishner reduction.
29. b) How will you synthesize cinnamic acid using Perkin’s and Knoevenagel

                reactions.

 

 

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