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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