1. The conductivity of polysilanes is due to

pie-delocalisation

sigma-delocalisation

presence of an impurity

proton transfer Ans.D

2. Planet Mars is called a "red planet" as it contains

iron compounds

organic dyes

Mo-S compounds

V-O compounds

3. If the bond is along the x-axis,which of the following combinations cannot form a molecular orbital?

px and s

p,and

p,and p"

p,and s

4. Which of the following molecules will form the strongest hydrogen bond with water?

H20

H2S

I2

PH3

5. In tetragonally elongated (acac =acetylacetonato), the 4th d-electron ofMn
resides in

d X2-y2

dZ2

dxy

dyz

6. SnCL3-is

triangular

pyramidal

T-shaped

tetrahedral

7. The bronze colored potassium graphite which is prepared by melting potassium
over graphite powder, is

an intercalation compound and a strong reducing agent

an adduct and a strong oxidizing agent

a covalent compound and a strong nucleophile· ....

an ionic compound and a strong electrophile

8. Using Wade's rule predict the structure ofB9HI4-.

closo

nido

arachno

scorpionato

9. The molecule with the smallest rotational constant among the following is (the number indicated within bracket is the bond length of the molecule)

LiH (0.98

NaH (1.1

KH (1.2

CsH (1.5

10. The number of IR and Raman active modes ofOCS are respectively

4,4

1

1,3

2,2

11. Symmetry number is the total number of symmetry equivalent orientations that can be arrived at using the rotational symmetry operations ofthe molecule. The symmetry number of cyclopropane is

2

3

5

6

12. Assuming full equipartition translational and rotational contributions, but only 20% vibrational contribution at 25°C, to the heat capacity at constant pressure the Cp for acetylene at 25°C is gas constant)

3.9 R

4.6 R

4.9 R

6.0 R

13. What is the maximum wavelength of the X-ray that can be used to obtain Bragg reflection from plane ofa simple cubic crystal with edge 1.5

3.5 A

1.5 A

3.0 A

1.54 A

14. When the spin on Mn2+ ion and 1is the spin on Cu2+ion, which one of the following arrangements represents ferrimagnetic ordering?

<img src='./qimages/1677-14.jpg'><br><br>

15. The electronic ground state configuration of C2 is

<img src='./qimages/1677-15.jpg'><br><br>

16. For a process at equilibrium, a plot of In K against liT gave a straight line with a negative slope of 7040 K-I . The deltaH0 value is =8.314 J K I mol-1= 0.0821 atm dm3 K"l mol-1)

58.53 kJ moL-l

5.853 kJ moL-l

5.853 kCal moL-l

785.3 kCal moL-l

17. The final product of the following reaction is

<img src='./qimages/1677-17.jpg'><br><br>

18. The product of the following reaction is

<img src='./qimages/1677-18.jpg'><br><br>

19. The characteristic peak in EI mass spectrum ofPhCH20H is at m/z

108

77

109

91

20. The C=O stretching vibrations in aliphatic aldehyde, ketone and ester, respectively occur at the approximate wave numbers:


l715 1745 anD 1735

1735, 1715 and 1745 cM-l

1745, 1715 and 1735 cm-1

1715,1735 and 1745 CM-l

21. A suitable reagent for the following reaction is

<img src='./qimages/1677-21.jpg'><br><br>

DIBAL-H

B2H6

NaBH4

(Ph3P)CuH

22. The product obtained in the following reaction is
CI2
Me Et3N
•
H OH 3)Me Me





t{°Ir.Me


Me Me




Me, N-O
g
Me Me
Ans.D
23. S-Mandelic acid has a specific rotation of+1580. The specificrotation ofamixture of(R)­mandelic acid and (S)-mandelic acid (mole ratio would be

+122.9°


-122.9°


+35.1°


-35.1°


Ans.D
24. Arrange the following intermediates in the order of decreasing basicity (strongest to weakest):
.... H2C=CH-II: CH3CH2-III CH3CH2O-IV: HC=C­

IV>I>II>III


fII>II>I>IV


III>IV>I>II


II>I>IV>III


Ans.D
"
25. Name the following reaction:


Hofmann-LoIDer reaction Barton reaction
Hofmann-LoIDer-Freytag Cope reaction
reaction
Ans.D





SECTIONB
(Answer any 10 questions)

1. In an adsorption experiment, the fractional coverage on surface was found to be 0.67 and
0.8 when the external pressure ofthe adsorbate was 1.0 and 2.0 atm., respectively. Determine the Langmuir coefficient, K.
2. Given the chemical reaction, A B P 2B, with a rate constant

write down the rate law for the disappearance ofA.


Determine the concentration ofA as a function oftime when 1.0 mol L-1 at t =O.





3. Consider the cell, Ag IAg2S041 H2S04 0.1 IH2 1 atm) IPt.

Write the half cell and full cell reactions.


If the standard EMF, EO of the cell at 25°C is -0.63 calculate the standard potential of the left hand electrode.


(c)IftheEMF,E ofthecellat 25°Cis-0.7V,calculatethevalue of(E-EO)at35°C. Assume ideal behaviour for the solution and the gas.
,.... ...
4. Show that the transition IA2 IA1 is electronic dipole forbidden in H20 molecule.
The series oflines in the microwave spectrum of IH 1271are spaced 12.8 cm-I apart. Calculate its bond length. [me27I) 126.9045 au]

..

5. Given the Hamiltonian, H d2/d<p2 +i.B corresponding to a particle on a ring in an external magnetic field B perpendicular to the plane of rotation, state the boundary conditions on the wave function and determine its eigenvalues and eigenfunctions.
•.

6.
Blood is said to be isotonic with 0.85% NaCl solution at 40°C. Assuming complete dissociation ofNaCI, calculate total concentration of various solutes in blood. What is its approximate freezing point? (Given Kf= 1.86 K/(mol

7.
The Debye temperature of two isomorphous ionic solids AB and XY are 300 K and 250 respectively. The lattice heat capacity of AB at 5 K is 0.05 J morl Estimate the heat capacity ofXY at 5 K and that of AB at 2 K.


.... ..

8. Draw a schematic diagram ofthe crystal structure ofpotassium chloride.

If the unit cell length is 6.295 calculate the density (in g of crystalline KCl. Atomic weights: K 39.098, CI 35.453


What is Schottky defect? If Schottky defect in the KCI crystal reduces its density by 6.25%, show a schematic representation of the defect in the unit cell.


....

..


9. Write the partition function for a 2-level system with the lower state of energy zero and the upper state ofenergy 8. Plot the partition function and fraction of molecules in the ith state as a function oftemperature, with temperature varying from zero to infinity.
....

•


10. The vibrational frequency ofa diatomic molecule AB is v. If another molecule CD has the same force constant and the mass of C and D are respectively twice that of A and express the vibrational frequency of CD in terms of v.
Classify BCl) and CH31 as either a prolate or an oblate symmetric top.
...

0,.


17
11. What are the possible products when hexafluoro cyclotriphosphazene is reacted with
dilithium salt of 1,3-propane diol in 1:1 mol ratio? Draw all the structures.

,ol ...•

18

12. Along with appropriate equations describe what happens When metallic potassium is dissolved in ammonia to form a dilute solution. When more potassium is added to form a concentrated solution. When solution and are evaporated carefully in vacuo. When is treated with Fe203 How can be considered a leveling reaction
....


13.
Formulate neutral 18 electron complexes ofchromium which contain only cyclo­pentadienyl and nitrosyl ligands and ii) cyclopentadienyl, carbonyl and nitrosyl ligands

Predict the structure of
Show by electron counting that C04(CO)12 obeys 18 electron rule.


14.
Calculate the spin only magnetic moment of Mn(CN)i-ion, making any reasonable assumptions about the ligand field.



The magnetic moment ofa four coordinate complex ofNf+ in a magnetically dilute crystalline substance is found to decrease from 2.8 B.M. at 300 K to about 0.1 B.M. at 77

K.
Suggest a possible explanation for this observation.


0,.

15. Draw an octahedron indicating clearly one ofthe 3-fold rotation axes. There is also an improper rotation axis coincident with the C3 axis. What is the order ofthis improper axis?
Draw the structures ofall possible isomers of [Cr(oxalate)2Ch]3-and label them.[2+3]
16. Using the following standard potentials; calculate the solubility product ofTlCl. TI+ e" EO=-0.34 V TICI TI CI EO =-0.56 V
Estimate the n,:tinimum potential difference needed for the electrolytic reduction of Ah03 to Al using the freeenergy given for the following decomposition at 500°C.
l
2/3 Ah03 4/3 Al 02 229 kcal mor



17. Violet Brown Violet Brown in coordinating B heat C cool D
Iodine Vapour solvents
A
Explain the above observation using M.O. energy level diagram for diatomic iodine molecule.
.... 0-.
18. The spin orbit coupling constant for Eu3 is -300 em-I. Explain the room temperature magnetic moment of 3.40 -3.60 "B.M. for this ion.
Explain why carbonyl complexes of lanthanides are difficult to prepare.
19. (a)Write the structures of the anion in Na2[B2(02)2(OH)4].6H20 cation in [OCNCOt[Sb3FI6]-and discrete anion in [Me2NH2h[As2CI9] (hint: C.N. of As is 6).
The solution state'3lp NMR spectrum of [HPFsr consists of a 20-line multiplet.
Explain. (Hint: I for IH, 31p and 19F is Y2 and natural abundance for all the nuclei is
"r­


Wilkinson's catalyst and how can you convert it to a heterogeneous catalyst? Explain with necessary equations.
..,. ·P ••
"..

21. Write an acceptable synthetic sequence for the conversion ofR-carvone to S-carvone.
-..

H
3
R-carvone
22. Give the structures ofproducts and in the following reaction arul briefly their formation with the intermediates and transition states.
(COClh
x



ArtMe ..
CH2Nz
C02H




0,.
23. The base-catalyzed hydrolysis ofethyl m-nitrobenzoate is 63.5 times faster than that of the unsubstituted ester under the same conditions. What will be the comparable rate of hydrolysis of ethyl p-nitrobenzoate? =0.71 and O'p-MeO
Consider the following dehydrohalogenation reactions. Explain the observed kinetic isotopic effects with relevant transition states.
Case I
H3C
NaOEtCH3CH2CH2-Br
EtOH •
H
kH 6.7
H3C koNaOEt
CH3CD2CHtBr
EtOH
D
Case II
CH3

H3C CH3
NaOEt
CH3CH2C-Br • Fe
I EtOH H 'CH3CH3 kH
1.4
CH3 ko
1
NaOEt /CH3
CH3CD2C-Br ..

I EtOH D 'CH3CH3
..


24. Provide the structures ofthe products with correct stereochemistry in the following reactions.
Cu THF




QCH' Li, NH3 •1 equiv. H2O •
PhCHO .. ....




25. Write the synthetic steps required to effect the following transfonnation.

Provide the detailed synthetic steps involved in the following transformation. MeO 0 OMe
... ..


26. How would you effect the following transformation?
MX·



Find the products A and B in the following synthetic sequence. Give the steps and intermediates of the reactions involved.
Na, Iiq. NH3/t-BuOH Mel
I A
.. B
LAH
KOH, EtOH
OMe NaH, Mel

Cu, pyridine, 160°C H30+
....

27. In the total synthesis ofpyranolide D the final step involves the following reaction sequence given below. Give the intermediates involved in this conversion.
aqueous LiOH

aqueous HF" HO


TBSO
oo
Pyranolide D
28. Givethestructures oftheproducts Aand Binthefollowingreactionwithcorrect stereochemistry. Rationalize the stereochemical outcome with appropriate transition states.


)lMQCI
.. B
Cui

..


30
29. Identify the structures of the compounds A and B in the following reaction. Provide the detailed mechanism involved in these steps.

..
K2C03 .. MeOH/H20 A 0 3 Zn/AcOH KOH/MeOH B

.... ..

30. Identify the structure of the compound with the spectra shown on the following page (page 32) and interpret the spectral data.
0..


..