Exam Details
| Subject | organic chemistry — i | |
| Paper | ||
| Exam / Course | m.sc in chemistry | |
| Department | ||
| Organization | alagappa university | |
| Position | ||
| Exam Date | November, 2017 | |
| City, State | tamil nadu, karaikudi |
Question Paper
M.Sc. DEGREE EXAMINATION, NOVEMBER 2017
First Semester
Chemistry
ORGANIC CHEMISTRY — I
(CBCS 2014 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. Account for the observation that terminal alkenes are
generally less stable than isomeric internal alkenes.
2. Explain why p-nitrobenzoic acid is stronger than
m-nitrobenzoic acid.
3. State and explain Saytzeff's rule with an example.
4. 1-iodotriplycene is inert both SN1 and SN2 type reactions
Explain.
5. What is non-benzenoid aromatic compound? Give two
examples.
6. Give the IUPAC names of the following
Sub. Code
4MCH1C1
AFF-4876
2
Wk 4
7. Assign configuration for the following geometrical
isomers.
8. Explain with an example, what is meant by chiral
molecule.
9. Define the term replication of DNA.
10. What are nucleic acids?
Part B x 5 25)
Answer all questions choosing either or
11. Between acetyl acetone and acetonyl acetone,
which is the stronger acid? Give reasons.
The benzoyl cation is substantially more
stable than the methyl cation. Give reason.
(2.5 2.5)
Or
Explain how carbanions are generated. Comment on
their stability.
AFF-4876
3
Wk 4
12. Give the mechanism of the unimolecular
elimination reactions.
Allyl halides undergo SN1 and SN2 reactions
faster than alkyl halides. Give reasons.
(2.5 2.5)
Or
Write notes on substitution nucleophilic internal
reactions.
13. Give an account of alternant and non-alternant
hydrocarbons.
Or
Discuss the concept of homoaromaticity with a
suitable example.
Define antiaromatic compounds. Give
examples.
14. Show how Prelog's rule can be used to determine
the absolute configuration of an optically active
alcohol.
Or
Write the correct configuration of the following
isomers of n-hexa-2,4-diene.
Z
E
Z. x 1
Draw atleast two Fischer projections of
s-2-butanol.
AFF-4876
4
Wk 4
15. Give a short synthesis of vitamin A.
Or
Narrate the functions of RNA.
Part C x 10 30)
Answer any three questions.
16. Discuss the formation and stability of carbenes and
nitrenes.
Why aniline is less basic than ethylamine?
17. Describe the effect of solvents on SN1 and SN2
reaction.
How will you differentiate E2 and E1cB
mechanism?
18. Explain the chemistry of cyclopentadienyl anion.
Narrate the aromaticity of annulenes.
19. How will you determine the configuration of
geometrical isomers using physical and chemical
methods?
Write Newman projections for the anti and eclipsed
conformation of n-butane.
20. Establish the structure of vitamin K.
—————
First Semester
Chemistry
ORGANIC CHEMISTRY — I
(CBCS 2014 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. Account for the observation that terminal alkenes are
generally less stable than isomeric internal alkenes.
2. Explain why p-nitrobenzoic acid is stronger than
m-nitrobenzoic acid.
3. State and explain Saytzeff's rule with an example.
4. 1-iodotriplycene is inert both SN1 and SN2 type reactions
Explain.
5. What is non-benzenoid aromatic compound? Give two
examples.
6. Give the IUPAC names of the following
Sub. Code
4MCH1C1
AFF-4876
2
Wk 4
7. Assign configuration for the following geometrical
isomers.
8. Explain with an example, what is meant by chiral
molecule.
9. Define the term replication of DNA.
10. What are nucleic acids?
Part B x 5 25)
Answer all questions choosing either or
11. Between acetyl acetone and acetonyl acetone,
which is the stronger acid? Give reasons.
The benzoyl cation is substantially more
stable than the methyl cation. Give reason.
(2.5 2.5)
Or
Explain how carbanions are generated. Comment on
their stability.
AFF-4876
3
Wk 4
12. Give the mechanism of the unimolecular
elimination reactions.
Allyl halides undergo SN1 and SN2 reactions
faster than alkyl halides. Give reasons.
(2.5 2.5)
Or
Write notes on substitution nucleophilic internal
reactions.
13. Give an account of alternant and non-alternant
hydrocarbons.
Or
Discuss the concept of homoaromaticity with a
suitable example.
Define antiaromatic compounds. Give
examples.
14. Show how Prelog's rule can be used to determine
the absolute configuration of an optically active
alcohol.
Or
Write the correct configuration of the following
isomers of n-hexa-2,4-diene.
Z
E
Z. x 1
Draw atleast two Fischer projections of
s-2-butanol.
AFF-4876
4
Wk 4
15. Give a short synthesis of vitamin A.
Or
Narrate the functions of RNA.
Part C x 10 30)
Answer any three questions.
16. Discuss the formation and stability of carbenes and
nitrenes.
Why aniline is less basic than ethylamine?
17. Describe the effect of solvents on SN1 and SN2
reaction.
How will you differentiate E2 and E1cB
mechanism?
18. Explain the chemistry of cyclopentadienyl anion.
Narrate the aromaticity of annulenes.
19. How will you determine the configuration of
geometrical isomers using physical and chemical
methods?
Write Newman projections for the anti and eclipsed
conformation of n-butane.
20. Establish the structure of vitamin K.
—————
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