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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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – APRIL 2012

CH 3502 – ORGANIC FUNCTIONAL GROUPS – I

 

 

 

Date : 24-04-2012              Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART – A

       Answer all the questions:                                                                                   (10 x 2 = 20 marks)

1. Vinyl halides are less reactive towards nucleophilic substitution reaction. Why?
2. Arrange the following bromides in the order of ease of dehydrohalogenation by alc. KOH.

 

 

 

3. What happens when propanone reacts with CH₃MgBr followed by hydrolysis?
4. Convert aniline to phenol.
5. Give the IUPAC names of the following ethers:

 

 

6. What happens when anisole( methoxy benzene) is hydrolysed with HI? Write the reaction.
7. Identify the compounds A and B:

H₂/Pd, BaSO₄                         HCN

C₆H₅COCl  ——————–→  A  ——————–→ B.

 

8. Two isomeric compounds A and B, with molecular formula C₃H₆O , form oxime with hydroxyl

amine.  Tollens test is answered by compound B only and iodoform  test is answered by compound

A only. Give the structures of A and B and state reason.

 

9. What is trans-esterification reaction.

 

10. Why is α-chloroacetic acid more acidic than chloroacetic acid ?

 

SECTION – B

Answer any eight questions:                                                                                    (8 X 5 = 40 marks)

11. Explain the reactions involved in the free radical chlorination of methane.
12. Predict the major product of the following reaction and explain.

(CH₃)₃ C CH= CH₂    + HBr  ————→ ?

13. Explain Reimer-Tiemann reaction.
14. Convert phenol to : i). benzaldehyde, ii) benzoic acid.                                           (2.5 + 2.5)
15. Describe the mechanism of hydroboration-oxidation of propene to 1-propanol.
16. What happens when tert-butyl methyl ether is hydrolysed using HI? Explain.
17. Write the mechanism of acid catalysed ring opening of ethylene oxide.
18. Explain Wittig reaction with a suitable example. Bring out the advantage of this reaction.

 

 

19. What are the products formed when acetophenone reacts with each of the following compounds?

Write the reactions.

2. i) LiAlH₄ in THF followed by hydrolysis ,        ii) HCN.                                                      (2 x 2.5)
3. Write a short note on Norrish type I reactions.
4. Differentiate between maleic and fumaric acids.
5. Write a brief account on the action of heat on α, β hydroxy acids.

SECTION – C

Answer any four questions:                                                                                     (4 X 10= 40 marks)

23. a) Describe E₁ mechanism with an example.
24. b) 2, 4 –dinitro chloro benzene undergoes nucleophilic substitution much faster than              Explain your answer.
25. a) Explain Kolbe’s reaction with mechanism.
26. b) Carry out the following conversions:
27. i) (CH₃)₂ CH CH₂OH ——–→  (CH₃)₃COH
28. ii) (CH₃)₃CBr ——————-→    (CH₃)₂ CH CH₂                                                 (2.5 + 2.5)
29. a) Describe alkoxymercuration and demercuration procedure for the synthesis of ethers

with an example.

1. b) How are the following compounds prepared from ethylene oxide?
2. i) butan-1-ol             ii)  2-methoxy ethanol.                                                                        (2+3)
3. Write a short note on :
4. a) Michael reaction b) Perkin’s reaction                                                                             (5+5)
5. Provide any one method to prepare the following compounds.
6. i) succinic acid ii) cinnamic acid iii) crotonic acid         iv) phenyl acetate
7. v) phthalic anhydride                                                                                                                      (5 x 2)
8. Compound A with molecular formula C₇H₆O on treatment with con.NaOH gives compounds B and
9. B on oxidation gives back A. A answers Tollens test but not Fehing’s test. Compound C on

acidification gives D (C₇H₆O₂). D gives brisk effervescence with aqueous NaHCO₃ and reaction with

ethanol in the presence of dil.H₂SO₄ gives a sweet smelling compound E. Identify A, B, C, D and E

and write the reactions involved.  Write all possible isomers of A.

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc., DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – NOVEMBER 2012

CH 5505 – ORGANIC FUNCTIONAL GROUPS – II

 

 

 

Date : 01-11-2012              Dept. No.                                        Max. : 100 Marks

Time : 9.00 – 12.00

 

PART – A

Answer ALL questions:                                                                                            (10 × 2 = 20)

 

1. How will you prepare ethylamine by Gabriel phthalimide synthesis?
2. How will you prepare diphenyl amine?
3. Methyl amine is more basic than aniline.Explain.
4. What are erythro and threo isomers?
5. Are all substances with chiral atoms optically active and resolvable?Explain.
6. What is meant by tautomerism?Give an example.
7. Give an example of molecular rearrangement involving migration of a group from oxygen atom to aromatic ring.
8. What is isoprene rule?
9. What are alkaloids?
10. Suggest any two tests to prove the presence of alkaloids.

 

PART – B

Answer any EIGHT questions:                                                                                   (8 × 5 = 40)

 

11. Arrange the following compounds in decreasing order of basicity and give reasons

for your answer.

Aniline , p-nitro aniline , m- nitro aniline , p-methyl aniline

12. Starting from aniline how will you synthesize the following?
13. i) sulphanilic acid
14. ii) benzoic acid

iii) phenyl isocyanate

13. Explain why racemic tartaric acid can be resolved but not meso tartaric acid. Give the chemical method of resolution.
14. Differentiate between enantiomers and diastereomers by taking suitable examples.

 

15. What happens when the following pair undergoes Claisen condensation?

Ethyl formate and ethyl acetate. Suggest a suitable mechanism.

16. What do you understand by active methylene group? Highlight its significance in organic synthesis.
17. Discuss the mechanism of pinacol – pinacolone rearrangement and give the evidence for carbonium ion intermediate.
18. Discuss Claisen rearrangement and give suitable evidence to confirm that the rearrangement is intramolecular.
19. Electrophilic substitution takes place in C-2 position and not in C-3 position in Furan. Explain.
20. Outline the synthesis of nicotine.
21. Explain the role of Herzig-Meyer method and Zeisel’s method in the structural elucidation of alkaloids.
22. Discuss the mechanism of nitration of benzene and explain why nitro group is a

deactivating group.

 

                                                            PART – C      

Answer any four questions:                                                                                    (4 × 10 = 40)

 

23. Give an example for the following name reaction.
24. Sandmeyer reaction ii)  Gomberg reaction

• Gattermann reaction iv) Carbylamine reaction

1. Schiemann reaction

 

24. a) How will you synthesize ortho and meta dinitro benzene from benzene . (6)
25. b) How will you distinguish primary secondary and tertiary amines by Hinsberg

method.                                                                                                                                 (4)

 

25. a) Explain asymmetric synthesis with suitable examples. (6)
26. b) Discuss the stereo chemistry of Walden inversion                                           (4)

 

26. How will you prepare the following from acetoacetic ester?
27. Acetonyl acetone ii) n-butyric acid       iii)  antipyrine
28. 3-methyl 2-pentanone v) Succinic acid
29. Complete the following:
30. Furan + maleic anhydride à ii) Pyrrole + C₆H₅N₂Cl + NaOH à

iii) Quinoline +KMnO₄à                  iv) Pyridine + nC₆H₅Li à

1. Thiophene + H₂SO₄ à
2. a) Explain the following rearrangements with mechanism.             (6)
3. Benzilic acid    ii) Beckmann.
4. b) Write the structure of piperine and give its synthesis. (4)

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc., DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – NOVEMBER 2012

 CH 3502 /4500 – ORGANIC FUNCTIONAL GROUPS – I

 

 

 

Date : 02-11-2012              Dept. No.                                        Max. : 100 Marks

Time : 9.00 – 12.00

 

PART-A

ANSWER ALL THE QUESTIONS:                                                                                     (10×2=20)

1. What is Walden inversion?
2. Arrange the following alkyl halides in the order of decreasing reactivity in S_N1 reaction

RI,  RCl,  RBr,  RF

3. Name the reagents used in the following conversions:
4. a) Ethyl amine into ethyl alcohol b) Acetone into t-butyl alcohol
5. What happens when ethanol is heated with I₂ and NaOH?
6. What are mixed ethers? Give examples.
7. How is anisole prepared from phenol? Give the IUPAC name of anisole.
8. What is Wolf- Kishner reduction?
9. What is crossed Cannizzaro reaction?
10. What is S_Ni reaction?
11. What happens when crotonic acid reacts with HBr?

 

PART-B

ANSWER ANY EIGHT QUESTIONS                                                                             (8×5=40)

 

11. Name the major product obtained when 2-chloro-2-methylbutane is treated with alc. KOH and give reason.
12. Compare the salient features of S_N1 and S_N2 reactions.
13. Explain the mechanism of Reimer-Tiemann reaction.
14. How are 1-propanol and 2-propanol prepared by hydroboration method? Explain why hydroboration violates Markovnikov’s rule.
15. How does phenol differ from aliphatic alcohols?
16. Explain Williamson’s synthesis of ethers.
17. Give reason for the following observations: a) Ethers have low boiling points than isomeric alcohols b) Diphenyl ether cannot be prepared by the dehydration of phenol.

 

18. Account for the following:
19. a) Carbonyl compounds are polar in nature
20. b) –CHO group is meta directing in aromatic electrophilic substitution reactions.
21. Explain the mechanism of conversion of acetaldehyde into β-hydroxybutyric acid.
22. Discuss the mechanism of reaction of benzaldehyde with KCN.
23. Arrange the following acids in the increasing order of acidity and give reason:

acetic acid, fluoroacetic acid, bromoacetic acid,  chloroacetic acid.

22. Give any two methods of preparation of succinic acid. What happens when
23. a) Succinic acid is heated with NH₃ b) Malonic acid is treated with P₂O₅. (3+2)

 

SECTION-C

       ANSWER ANY FOUR QUESTIONS:                                                                      (4×10=40)

 

23. Discuss the effect of the following factors on E1 reaction:
24. a) Structure of alkyl halides b) Strength of the base   c) Polarity of the solvent
25. How is phenol prepared from benzene? How are the following compounds obtained from

phenol?  a) benzene b) picric acid c) azo dye

25. a) How is ethylene oxide prepared? Mention its important synthetic uses.
26. b) Discuss the cleavage reactions of ethers by HI.
27. Discuss the following reactions with mechanism
28. a) Wittig reaction b) Norrish type- I reaction (5+5)
29. a) Discuss the mechanism of Michael addition reaction.
30. b) Discuss the action of heat on dicarboxylic acids.
31. a) Predict the products of the following reactions:
32. i) Acetamide  +  P₂O₅   →
33. ii) Acetyl chloride  +  H₂/ Pd-BaSO₄   →

iii)  Methyl acetate  +  Ethanol  →

1. iv) Adipic acid  +  (CH₂)₆(NH₂)₂   →
2. v) Acetaldehyde  +  malonic ester  →

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