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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