.

IIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIII

III Semester

B.Sc.Ed./M.Sc.Ed.

Examinati~n,

Nov./Dec.

2015

(Scheme: CBCS) Chemistry Organic Chemistry -I Time: 2 Hours

Max. Marks:

Instruction 1. a) Assign

50

Answers should be brief and specific.

R or S configuration

to asymmetric

carbon(s)

in the following

molecules.

<=.o~~ I'.f~-s~ i) 1-H

3

NH:2-

) ,~ . II L~~ C~ "":::2:-S"i-\ "

.

3

b) Designate E/Z configuration

to the following double bonded compounds,

i)

2

c) Write short notes on conformational

analysis of n-butane

5

OR

P.T.O

I IIIIII IIIII IIIII IIIII IIIII IIIIIIII

-2-

88850

2. a) State sequence Rules. Explain with suitable examples the application of sequence rules in assigning absolute configuration

5

to stereoisomers.

b) How will you distinguish between configuration and conformation ? Discuss the various conformations of cyclohexane and comment on their stabilities.

5

3. a) Predict the product(s) in the following reactions i) (CH3)2CuLi

dryether

+ CH3CH2Br

-CH ii) CH3CH I CH3

~

?

?

= CH2 + HCI

-COOEt -COOEt

iv) CH3 -C =C -CH3

1) OH2)H+ 3) L1-

? CO2

4

-)- ?

2) H2O2/NaOH b) Write short notes on the following i) Baeyer's

s~rain theory

ii)- 1, 2 and 1, 4 addition

:

and its limitations. reactions

6

of alkadienes.

OR

4. a) How do you explain the following ? i) Propene on reaction with HBr in the presence of peroxides yields 1-bromopropane. 1i) 2-bromobutane on dehydrohalogenation as major product.

using alcoholic KOH gives 2-butene

CH3

iii)

I N

CH3

CH2 -CH3

OH on heating

yields ethene

as major

I CH2

CH2 -CH3 6

product and propene as minor product. b) An alkene A having molecular formula C5H10on ozonolysis yields acetone and acetaldehyde as products. Identify the structure of alkene A. c)

How dienes of dienes

?

are classified

? How do you distinguish

between

various

2

classes

2

.

I IIIIII IIIII IIIII IIIII IIIII IIIIIIII

88850

-3-

5. a) Discuss the structure of Benzene in terms of resonance and molecular orbital

7

concepts. b) Explain the mechanism limitations.

of Friedel

crafts alkylation

reaction ,

and mention

its

3 OR 6,

a) Draw energy b) State

profile diagram

Huckel's

non-aromatic

for any electrophilic

rule. Which

of the following

? Offer suitable

explanation

aromatic

substitution

are aromatic,

anti-aromatic

reaction.

4

and

for, each :

~

j) ~ H

ii)O '\--\ iii)

~

iv)

IT rI""1~ d ""=. .Ir-c-

6

-~ 7

a) Discuss and compare the mechanism

of 8N1 and 8N2 reactions of

haloalkanes.

6

b) How do you synthesise the following compounds i)

:

DOT

4

ii) Chloroform OR 8. a) How do you explain the following

?

i) 8N1 reactions are accompanied

by rearraRgement.

4

ii) Allyl chloride is more reactive than Vinyl chloride. b) Giving evidence for the formation of benzyne intermediate, discuss the elimination addition mechanism for nucleophilic

aromation substitution

reaction.

6

.

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-4-

9. Answer

any five of the following

i) How will you determine ii) Explain

asymmetric

:

10

the configuration

synthesis

of Geometric

with a suitable

iii) Write a brief note on the acidity iv) What is a regioselective

I IIIIII IIIII IIIII IIIII IIIII IIII IIII

reaction

viii)

Discuss

the addition

of alkynes. ? Explain

substitution

of Friedel-

-elimination

?

example.

with suitable

v) How do you convert benzene into 1, 4-cyclohexadiene mechanism involved. vi) Discuss the mechanism

isomer

example.

? Discuss the

crafts acylation reaction

mechanism

of nucleophilic

aromatic

with an example.

*