University of Delhi 2005-2nd Year B.Sc Chemistry V Organic Year : - Question Paper

Q.I. (a) A and Bare 2 isomeric dicarboxylic acids whose molecular formula is C4 H4 O4. A adds one mole of bromine to provide a product from which a pair of enantiomorphs may be resolved. B adds one mole of bromine to yield a compound which is not resolvable. Suggest structural formulae for A and B and the 2 dibromo compounds. 4
(b) Draw all possible stereoisomers for the subsequent and state which are optically active, inactive forms:
(i) MeCHOHCHOHMe
(ii) MeCHClCO2H

Q.2. (a) organize the subsequent in order of increasing b.p. and provide your reasons:
(CH2OH)2, (CH2OMe)2, HOCH2CH2OMe
(b) elaborate the effects of the subsequent groups on the basicity of aniline when in p-position:
(i) -NO2
(ii) -OCH3
(iii) -N(CH3)2
(c ) o-Nitrophenol has a lower b.p. and lower water solubility than the pisomer. discuss.
(d) The sodium salt of sulphanilic acid can be readily acetylated with AC2O, but not the free acid. discuss.
Q.3. (a) provide the E-Z designation to the subsequent compounds:
Image no.1
(b) How would you use:
(i) Acetoacetic ester synthesis to prepare 2-pentanone ?
(ii) Malonic ester synthesis to get hexanoic acid ? 2
(c ) What happens when glycerol is reacted with :
(i) HIO4
(ii) KHSO4.

Q. 4. (a) How will you prepare the following:
(i) p-Bromotoluene from ptoluidine;
(ii) p-Dinitrobenzene from pnitroaniline;
(iii) Phenol from cumene;
(iv) Picric acid from chlorobenzene. 4
(b) Coupling of benzene diazonium chloride takes place either under mild alkaline or mild acidic conditions. discuss by taking a suitable example.

Q. 5. (a) Write short notes on the following:
(i) Tautomerism;
(ii) Fischer projection formula;
(iii) Cannizzaro’s reaction.

Q. 6. (a) What is the action of heat on a-ß-and hydroxy acids ?
(b) Chlorobenzene is less reactive than benzyl chloride towards nucleophiles. discuss.
(c ) Image no.2

Earning:   Approval pending.