Osmania University (OU) 2006 B.Pharm 2nd year Organic Chemistry Main, - Question Paper

1. (a) describe hybridization and discuss sp2 hybridization with the help of 1 example.

(b) define the mechanism of chlorination of methane.

OR

(c) elaborate free radicals? How are they formed? explain free radical addition of alkenes with the help of suitable example.

(d) Mention any 1 method of preparation and any 2 chemical reactions of cyclopentane.


2. (a) Write a short note on the following:
(i) Bond dissociation energy (ii) Polarity of bonds (iii) Dipole moment

(b) With the help of one example each, discuss acidity of 1-alkyne and stability of conjugated alkadienes.

(c) Write a note on
(i) Pauli’s exclusion principle
(ii) Intermolecular forces
(iii) Inductive effect
(iv) Mesomeric effect
(v) Resonance

(d) discuss the phenomenon of tautomerism. provide two examples.


3. (a) define the mechanism of SN1 reaction.

(b) define the mechanism of E2 reaction.

OR

(c) How will you prepare ethers by alkoxymercuration and demercuration and by Williamson’s synthesis?
provide one example of every and discuss the mechanism of reaction.

(d) discuss the Grignard synthesis of 1°, 2° and 3° alcohols.


4. (a) define any two methods of preparation of ketones along with mechanism.

(b) provide any two examples with mechanism of nucleophilic addition reaction to ketones.

OR

(c) provide any three methods of preparation of aldehydes.

(d) discuss Cannizaro's reaction and Pinaco-Pinacolone rearrangement.


5. (a) elaborate diazonium salts? How will you convert benzene to m-nitrotoluene and m-dibromobenzene?

(b) (i) Aniline (ii) P-Aniline (iii) P-nitro Aniline (iv) Ammonia

OR

(c) How will you prepare acetoacetic ester? provide one application of acetoacetic ester synthesis.

(d) provide any two methods of preparation and one reaction of acetic acid.

Earning:   Approval pending.