CHEMISTRY
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PAPER·II
SECTION A
I. Answer any four of the toll owing: (Each answer m aboui I 30
Why cyclopentadienyl anion is stable but not its cation? give a method for its preparation:
What are singlet and triplet methyl nitrenes? Explain their additions to cis-butene-2.
Apply Frontier molecular orbital method to predict the reaction conditions for
<img src='./qimages/1456-1c.jpg'> and <img src='./qimages/1456-1c1.jpg'> cycloadditions.

X1(C9H8) compound
reduction yields. X2(C9H10)and
(ii)also on bromination yields X(C9H8)Br2,..X1..X2 and X on oxidations give same
die arboxylic acid which forms its anhydride. Suggest structures for compounds X1,X2, and
X3.
(e)Compound X1(C6H7N) with chloroform and sodium hydroxide in ethanol, gives X2(C7H5N)
which on reduction forms X3(C7H9N), a secondary amine Assign structure to compounds
X1 X2 and X3.
2.(a)<img src='./qimages/1456-2a.jpg'>
an aromatic compound? Give- its three other resonance hybrids.
(b)Describe the applications of isotope effects in the study of the reaction mechanisms, Give
suitable examples.
(c)Indole (C3H7N) on bromination in carbon tetrachloride yields a monobromo derivative
(C8H6NBr). Explain in the nature of this reaction. Suggest structure for the bromo derivative.
(d)Why the base catalysed hydrolysis of
<img src='./qimages/1456-2d.jpg'>

which gives two isomeric alcohols, is faster than the hydrolysis of isopropyl chloride? Assign
Structures to these two isomeric alcohols.

3.(a)Hexatrience-cyclohexadiene electro cyclic inter-con-versions- can be carried out thermally as
well as photo chemically. Predict the stereo chemistry of these inter conversions.
(b)Describe the steps and mechanisms involved in the preparation of 1-methyl isoquinoline by
Bischler-Napieralski procedure.
2-propanediol with mineral acid gives a ketone (C9H10O), Name and explain the
reaction.
(d)what is Saytzeff elimination rule Explain the major mod minor elimination products formed
in the following:
<img src='./qimages/1456-3d.jpg'>


4.(a)Predict reaction conditions for 1,3-antrafacial and suprafacial sigmatropic shifts,
(b)Describe the mechanisms involved in the synthesis of m-chlorobenzoic acid using p-chloronitrobenzene
by von Richter reaction.
src='./qimages/1456-4c.jpg'>

undergoes Hofmann elimination reaction. Name the reagents used, and expected reaction
products.
(d)Suggest and explain the reaction products formed by treating 2-choloronaphthalene with
sodamide in liquid ammonia.
(10x4-40)
SECTION B
5. Answer any four questions (Each 3llSI<lr in about 150 words):
Describe a preparation Terylene
<img src='./qimages/1456-5a.jpg'>

(b)Bring out the basic difference between Norrish type I and Norrish Type II reactions. explain
taking suitable examples.
(c)Butadiene in singlet state gives intra-molecular products. Explain giving suitable examples.
(d)Describe the applications of SeO2 as an oxidizing reagent Explain the oxidation of phenyl
benzyl ketone with this reagent in aqueous acetic acid at 89 degC.
(e)Discuss electron spin resonance and its applications.

6.(a)Give an example of ribonucleic acid to show the basic- bonds present in its primary
and secondary structures.(20)
(b)Explain the mechanisms for the following reactions:
src='./qimages/1456-6b1.jpg'>
src='./qimages/1456-6b2.jpg'>
(iii)<img src='./qimages/1456-6b3.jpg'>
src='./qimages/1456-6b4.jpg'>


7(a)Explain fluorescence and photochemical singlet state transitions.
(b)Predict and explain the reaction products in the following:
src='./qimages/1456-7b1.jpg'>
src='./qimages/1456-7b2.jpg'>
(c)The mass spectrum of an ester 150) has anion. m/e 118 Which of the following isomeric
compounds would be expected to have this ion? Explain
<img src='./qimages/1456-7c.jpg'>

Acetone absorbs light at 280, 187 and 154nm What types of transitions cause these
absorptions?
(10X4 40)

8.(a)How would their spectra of the following compounds differ in the region 4000-1650cm-1?(10)
<img src='./qimages/1456-8a.jpg'>
what region of the PMR spectrum would the marked b and c protons of the following
compound, be expected to have their signals? 10)
<img src='./qimages/1456-8b.jpg'>
The PMR spectrum of a compound (C7H7NO3), has signals at delta7.9 doublet), 7.1(2H,
doublet) and 3.9 (3H singlet) suggest and justify its assigned structure