Chemistry Paper V Organic Chemistry Previous Year Question Paper Year 2005 : IInd Year

Q.I. (a) A and Bare two isomeric dicarboxylic acids whose molecular formula is C4 H4 O4. A adds 1 mole of bromine to give a product from which a pair of enantiomorphs may be resolved. B adds 1 mole of bromine to yield a compound which is not resolvable. Suggest structural formulae for A and B and the two dibromo compounds. 4

(b) Draw all possible stereoisomers for the following and state which are optically active, inactive forms:
(ii) MeCHClCO2H
Answer :

Q.2. (a) Arrange the following in order of increasing b.p. and give your reasons:
(CH2OH)2, (CH2OMe)2, HOCH2CH2OMe

(b) What are the effects of the following 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. Explain.

(d) The sodium salt of sulphanilic acid can be readily acetylated with AC2O, but not the free acid. Explain.
Answer :

Q.3. (a) Give the E-Z designation to the following 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.
Answer :

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. Explain by taking a suitable example.
Answer :

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

Q. 6. (a) What is the action of heat on α-β-and hydroxy acids ?

(b) Chlorobenzene is less reactive than benzyl chloride towards nucleophiles. Explain.

(c ) Image no.2
Answer :

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