LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

GH 11

THIRD SEMESTER – APRIL 2008

CH 3502 – ORGANIC FUNCTIONAL GROUPS – I

 

 

 

Date : 26/04/2008                Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

PART – A

                                                                        (10 x 2 = 20 marks)

Answer ALL the questions.

1. Explain why 1⁰ alkyl halides undergo nucleophitic substitution only by S_N2.
2. Name the products obtained in the addition of HBr to propere in the absence and presence of peroxide.
3. What happens when acetophenone is treated with I₂ / NaOH?
4. Why p-nitrophenol has higher boiling point than o-nitrophenol?
5. What are mixed ethers? Give examples.
6. How is anisole prepared? What happens when anisole is treated with excess of HI?
7. Name the products obtained form 2-hexanone in Norrish type II reaction.
8. What is Cannizzaro’s reaction?
9. Compare and account for the acidity of acetic acid, prop ionic acid and chloroacetic acid.
10. What is the action of heat on malonic and succinic acids?

 

PART – B

                                                                        (8 x 5 = 40 marks)

Answer any EIGHT questions.

1. Give any two methods of preparation of chlorobenzene. Starting from chlorobenzene how are the following compounds prepared?

1. a) o-dichlorobenzene b) aniline      c) DDT

1. Discuss the effect of nature of substrate, nucleophile and solvent in nucleophilic substitution.
2. a) Account for the acidity of phenol

1. b) How would you prepare the following compounds from phenol?
2. i) o – Cresol ii) Benzene iii) Phenyl acetate.

1. Explain the nitration of Phenol with Mechanism.
2. How are alcohols prepared by hydroboration method? Give the mechanism of the reaction.
3. a) Why are ethers less reactive than epoxides?

1. b) How is ethylene oxide prepared? How does it react with methanol and ammonia?

1. a) Write the IUPAC names of ethyl methyl ether and anisole.

1. b) Give any two methods of preparation of diethyl ether. Mention a reaction where ether behaves as a Lewis base.

1. What is Reformatsky reaction? How is it useful in organic synthesis?
2. Discuss Norrish type I reaction.
3. Give the products of the following reactions.

1. Benzaldehyde +
2. Acetaldehyde + Malonic ester
3. Benzaldehyde
4. Acetone +
5. Acetaldehyde +Malonic ester

 

1. a) What is meant by transesterification?

1. b) Discuss the action of heat on and – amino acids.

1. Give any two methods of preparation of adipic acid. Write its IUPAC name. How would you convert adipic acid into cyclopentanone and NYLON-6,6?

 

PART – C

                                    (4 x 10 = 40 marks)

Answer any FOUR questions.

1. Explain E1 mechanism of dehydrohalogenation of alkyl halides. Discuss the orientation and reactivity of alkyl halides in dehydrohalogenation.
2. a) Identify the products in the following sequence of reactions

Isopropyl alcohol ABC D

1. b) Discuss the following reactions of phenol
2. i) Coupling reaction ii) Reimer – Tiemann reaction

1. a) Explain Williamson’s synthesis of ethers with mechanism.

1. b) Discuss the cleavage of ethers with HI

1. Discuss the following reactions with mechanism

1. a) Wittig reaction b) Benzoin condensation

1. a) How do you convert benzaldehyde into cinnamaldehyde? Explain with mechanism.

1. b) Arrange the following compounds in the increasing order of acidity. Give reason. Benzoic acid, p-toluic acid, p-nitrobenzoic acid and p-chlorobenzoic acid.

1. a) How is acetyl chloride prepared from acetic acid? How are the following compounds prepared from acetyl chloride?

1. Acetaldehyde ii) Acetophenone  iii) Acetone
2. b) Give the mechanism of esterification.

 

 

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