Download LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION –CHEMISTRY
SUPPLEMENTARY EXAMINATION – JUNE 2007
CH 4500 - ORGANIC CHEMISTRY - II
Date & Time: 25/06/2007 / 9:00 - 12:00
Dept. No.
Max. : 100 Marks
PART-A
Answer ALL questions.
(10  2 = 20)
1.
How will you distinguish chemically methanol from ethanol?
2.
‘E1 reactions are accompanied by rearrangement where as E2 reactions are not’. Why?
3.
Complete the following reaction and write the name of the reaction.
Re d P
Cl2 , 

CH3COOH
4.
Draw the structure of the following compounds.
a) bicyclo[2.2.1] heptane
b) 2-chloro-1-methyl cyclohexane
5.
Arrange the following acids in the increasing order of their acidity. Justify your answer.
CH3CH2CH(Cl)COOH, CH3CH2CH2COOH, ClCH2CH2CH2COOH,
CH3CH(Cl)CH2COOH
6.
What is Huckel rule? Write the structure of two compounds that follow this rule.
7.
What is Gattermann-Koch reaction?
8.
How is cinnamic acid prepared from benzaldehyde?
9.
What is Sandmeyer reaction?
10. How will you convert cumene into phenol?
PART-B
Answer any eight questions.
(8  5 = 40)
11. a) How will you obtain an epoxide from an alkene? What happens when the epoxide is
subjected to hydrolysis?
(3)
b) Write a note on Williamson’s synthesis.
(2)
12. Explain the mechanism of dehydration of ethyl alcohol to ethylene.
13. Draw all the conformers of cyclohexane and explain their stabilities with potential energy
diagram.
14. a) Write the mechanism for the reduction of CH3COOC2H5 by LAH.
b) How will you prepare isobutyl alcohol using a Grignard reagent?
15. An amide(A) having molecular formula C3H7ON on hydrolysis gives an acid C3H6O2(B)
which upon chlorination in the presence of red phosphorus produces a chloroacid(C).The
latter on boiling with aqueous NaOH and subsequent acidification forms lactic acid(D).Write
the reactions and the structure of A, B, C and D.
16. Explain the stereochemistry of the addition of bromine to maleic and fumeric acids.
17. Give the mechanism of sulphonation of benzene.
18. What happens when benzaldehyde is heated with alcoholic KCN solution? Explain the
mechanism.
19. How will you synthesise the following compounds from benzaldehyde?
a) Mandelic acid b) m-Benzaldehydesulphonic acid c) Toluene (2+2+1)
20. Write a note on acidity of substituted benzoic acid.
21. How will you prepare the following compounds from benzenediazonium chloride?
a) p-aminoazobenzene b) benzene c) anisole d)benzonitrile e) phenol
22. Write the mechanism of dienone-phenol rearrangement.
PART-C
Answer any four questions.
(4  10 = 40)
23. a) List the possible products in the order of decreasing yield from the reaction of
3-bromo-2, 3-dimethyl pentane with alcoholic KOH. Justify your answer.
(6)
b) Compare SN1 and SN2 reactions.
(4)
24. a) What are the postulates of Baeyer’s strain theory? What are its limitations? (6)
b) Explain the relative stabilities of first three cycloalkanes with the heat of
Combustion.
(4)
25. a) Explain the mechanism of hydroboration-oxidation method for the preparation of
n-propyl alcohol.
(6)
b) How will you convert isopropyl alcohol into n- propyl alcohol.
(2)
c) Why oxymercuration-demercuration method of preparation of alcohols follows anti
addition.
(2).
26. a) Explain why benzene undergoes electrophillic substitution reactions whereas alkenes
undergo addition reactions.
(4)
b) What happens when benzene reacts with carbon monoxide and hydrogen chloride in the
presence of AlCl3? Explain the mechanism.
(4)
c) How will you convert o-toluidine into o-toluic acid?
(2)
27. a) Explain any five synthetic applications of malonic ester.
(5)
b) Explain why p-nitroaniline is less basic than aniline? Explain.
(2)
c) What are the products obtained by reduction of nitrobenzene under different conditions?
(3)
28. a) How does phenol react with the following reagents?
(5)
i) Zn/heat ii) Br2/H2O iii) HNO2 iv) H2/Ni v) CH3COCl/NaOH
b) What happens when pinacol is treated with dilute or moderately concentrated H2SO4?
Explain with mechanism.
(5)
*************
2