LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION –CHEMISTRY
SUPPLEMENTARY EXAMINATION – JUNE 2007
CH 2500 - ORGANIC CHEMISTRY - I
Date & Time: 26/06/2007 / 9:00 - 12:00
Dept. No.
Max. : 100 Marks
PART – A
Answer ALL the questions
01.
02.
03.
04.
05.
06.
07.
08.
09.
10.
(10 ×2 = 20 marks)
What are conformers? Give an example.
Draw the eclipsed and staggered structure of pentane
Which of the following compounds can exist as cis-trans isomer? Draw and label the cis-trans
isomers.
a) CH3CH=CHCH3
b) (CH3)2C=CH CH3
Arrange the following in the increasing order of priority in assigning R-S configuration.
a) –H, –OH, –CHO, –CH3
b) –H, –N(CH3)2, –OCH3, –CH3
Predict the product of the reaction of 3-bromocyclohexene with alcoholic KOH.
What is pyrolysis? Give an example.
Write a note on peroxide effect.
Write a note on acidity of acetylene.
State Markovnikov’s rule. Give an example.
Name the following compounds
a) CH3-CH=CH-CH2-CH=CH-CH3
b) CH3-CH(CH3)-CC-CC-CH3
PART – B
Answer any EIGHT questions
11.
12.
‘Dienes are more reactive towards free radical additon’. Why?
Predict the product of Diel’s-Alder addition reaction of 1,3-butadiene with
O
O
a)
O
O
13.
14.
15.
16.
17.
18.
19.
(8 × 5 = 40 marks)
H3C
H
c)
b)
H
COOH
O
Define torsional strain.Explain the conformational analysis of ethane.
a) Define atropisomerism. Give an example.
b) Are allenes optically active? Give reasons.
Distinguish between stereospecific and stereoselective reactions. Give suitable examples.
Draw the stereoisomers for the following compounds and state which of the following has a meso
compound.
a) 3, 4-dimethylhexane
b) 2-bromo-3-methylpentane.
Predict the products in the following reactions
Zn, Alcohol

 ?
a) C2H5-CBr2-CBr2-CH3 2
b) CH3-CH2-CH=CH-CH3 + HBr  ?
What happens when butylene undergoes catalytic oxidation? Write the mechanism of the
reaction.
How is neo-pentane synthesized by Corey-House method? Write the mechanism of reaction.
20.
21.
What are the products formed when 1-butyne is treated with a) hot KMnO4 and
b) hypobromous acid
Predict the products of the following reactions
a) CH3-CH=CH2
+
C
500



Br2
?
 ?
b) 3 CHCCH3   
How are the following compounds synthesized?
a) 1-pentene
b) 2-butyne
Re d hot tube
22.
PART – C
Answer any FOUR questions
(4 × 10 = 40 marks)
23.
Draw the various conformers that result from rotation about the C2-C3 bond of butane. Explain
using a potential energy diagram.
24. ‘1, 2-addition product of conjugated dienes is the kinetic product whereas the
1,4-product is thermodynamic product.’ Explain.
25.
a) Assign R/S configuration to the following.
CH2OH
HO
CH3
H2C
HC
CH2CH2CH2OH
(i)
Br
CH(CH3)3
H
OH
H3CH2C
CH2Br
(ii)
H
CH2CH3
CH3
C(CH3)3
H3C
(iv)
(iii)
b) Draw the E and Z isomers of each of the following compounds.
Cl
Cl
(i) CH3CH2C CHCH2CH3
26.
27.
28.
(ii)
Br
CH CCH3
a) How will you synthesize isopropyl alcohol from n-propyl alcohol?
b) Write equations for the preparation of n-butane from
i) n-butyl bromide
ii) ethyl bromide
How will you synthesize
a) propylene from n-propyl bromide
b) n-propyl alcohol from propylene
c) trans-2-butene from 2-butyne.
Explain the following with suitable examples
a) Acetylene forms salt with sodium whereas ethylene does not.
b) Addition of hypohalous acid on to alkynes result in aldehydes or ketones.
c) Alkanes are less reactive than alkenes.
d) Ozonolysis on to alkenes and alkynes forms different products.
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