COMBINED COMPETITIVE EXAMINATION (MAIN)
CHEMISTRY Paper-II Time 3 hours Full Marks 200 Note: The figures in the right-hand margin indicate full marks for the questions.

Attempt five questions in all.


Question No. 1 is compulsory.


1. Answer any ten of the following 4xlO=40

Draw the resonance structure of


Write the IUPAC name of the following compounds
Br Cl













NH2
Which of the following atoms are NMR active?
1H 12C 13C 14N 160
8


Write the names of DNA bases.


What happens when two molecules of acetone are reacted in presence of base?


(jJ Write the coupling constants of ortho-, meta-and para-hydrogens of benzene.
23/DDS-201S/CHEM-PII/Set-A 1 p.T.a.

Arrange the foll?wing molecules in order of stability H CH•
3

H3C H
H


.H .



How many IH-NMR signal(s) would you expect 10 dimethyl ether (CH3-O-CH3 Explain.


What is Beer-Lambert law? Write the mathematical form of it.


Describe the application of ESR on the study of free radicals.


How will you distinguish the following molecules by IR spectroscopy? OH



&HO

9
CHO

Which of the following molecules has higher dipole moment?
CHCl3
CCl4

23/DD5-2015jCHEM-PIIjSet-A 2

2. Answer any eight of the following 5x8=40

What do you mean by red shift in IR spectroscopy?


Why CO2 molecule is not IR active?


Draw the IH-NMR spectra of the following molecule
CH3-CO-CH2CH3



How many peaks will you get in the mass spectra of phenol?


Identify the product(s) of the following reaction with mechanism 80 DC


Give an account of the role played by IR spectra in the structure determination of metal carbonyls.


Write a note on Michael addition reaction.


Why is tetramethylsilane used as internal standard in NMR spectra?


What is the difference between substitution and elimination reactions?


Discuss, the structure of methane and ethylene with hybridization.




3. any five of the following 8x5=40

Write the differences between SN 1 and SN2 substitution reactions.


Predict" the product of the following reaction with suitable mechanism


Ph'fPh H3C C
VH3

I )
OH OH

23/DDS-201SjCHEM-PIIjSet-A 3 [P.T.O.


Differentiate the following molecules by IR sp"ectroscopy


H3C-CH2-OH


H2C=CH-CHO




Define molecular ion peak and base peak.


What is vulcanization? Why is rubber vulcanized?


Discuss various types of stretching vibration presents in IR spectroscopy.


Discuss the effects of electron donating and withdrawing group in UV


4. Answer any four of the following lOx4=40

Describe the synthesis of polystyrene.


What is Reimer-Tiemann reaction?


Predict the product of the following reaction with suitable mechanism:


-OH



ifH°
mole)
Explain the ,following reaction with proper mechanism

0"
II LiAlH4
U-C-O-CH3 h CH20H

Discuss about the Reformatski reaction.


What is chromophore? Give examples.



23/DD5-2015jCHEM-PIIjSet-A 4

20x2=40

5. Answer any two of the following

Discuss the use of NBS and Najliq. NHs in organic synthesis.


Discuss about the aldol condensation reaction..


Give a brief note on silicones and their applications.


6. Answer any four of the following: 10x4=40

Write a note on free radicals.


Which of the following carbocations is more stable? Discuss with proper reason


Allylic carbocation


Benzylic carbocation




Explain the structure and bonding in polyphosphazenes.


Borazine is called inorganic benzene. Why?


What is the origin of the hyperfine splitting in an ESR spectrum?


7. Answer any two of the following 20x2=40

Discuss El and E2 elimination reactions.


Explain with the help of pericyc1ic reactions, cyc1oaddition is thermally allowed or not.


Write the effects of base on elimination reaction.


8.
Explain different types of photochemical reaction of organic compounds with suitable examples. 40

9.
Write notes on polyvinyl chloride and nylon. 40

10.
Discuss about the kinetic and thermodynamic control reactions with suitable examples. 40




23/DD5-2015/CHEM-PII/ Set-A 5 DD5-10