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Question : 26
Total: 26
(a) Write the structures of A and B in the following reactions :
(i)CH 3 COCl
A
B .
(ii)CH 3 MgBr
A
B .
(b) Distinguish between :
(i)C 6 H 5 − COCH 3 and C 6 H 5 − CHO ,
(ii)CH 3 COOH and HCOOH .
(c) Arrange the following in the increasing order of their boiling points :
CH 3 CHO , CH 3 COOH , CH 3 CH 2 OH .
OR
(a) Write the chemical reaction involved in WolffKishner reduction.
(b) Arrange the following in the increasing order of their reactivity towards nucleophilic addition reaction :
C 6 H 5 COCH 3 , CH 3 − CHO , CH 3 COCH 3
(c) Why carboxylic acid does not give reactions of carbonyl group ?
(d) Write the product in the following reaction.
CH 3 CH 2 CH = CH − CH 2 CN
?
(e) A and B are two functional isomers of compoundC 3 H 6 O . On heating with NaOH and I 2 isomer B forms yellow precipitate of iodoform whereas isomer A does not form any precipitate. Write the formulae of A and B .
(i)
(ii)
(b) Distinguish between :
(i)
(ii)
(c) Arrange the following in the increasing order of their boiling points :
OR
(a) Write the chemical reaction involved in WolffKishner reduction.
(b) Arrange the following in the increasing order of their reactivity towards nucleophilic addition reaction :
(c) Why carboxylic acid does not give reactions of carbonyl group ?
(d) Write the product in the following reaction.
(e) A and B are two functional isomers of compound
Solution:
(a) (i) CH 3 COCI
(ii)CH 3 MgBr
CH 3 COOH
CH 3 COCI + HCl + POCl 3
(b) (i)C 6 H 5 CHO being an aldehyde reduces Tollens' reagent to shining silver mirror whereas C 6 H 5 COCH 3 being a ketone does not.HCOOH gives silver mirror test with Tollens' reagent whereas ethanoic acid does not.
HCOOH + 2 [ Ag ( NH 3 ) 2 ] + + 2 OH − → 2 Ag ↓ + 2 H 2 O + CO 2 + 4 NH 3
CH 3 COOH
No silver mirror
OR(a)C 6 H 5 COCH 3 < CH 3 − COCH 3 < CH 3 − CHO
(c) Carboxylicacids do not give reactions of carbonyl groups as it enters into resonance with lone pair of -COOH groups thereby making the carbon atoms less electrophilic.
− CH 2 CN
CH 3 CH 2 CH = CH −
(e)
+ NaOH + I 2 → No yellow precipitate
+ 3 NaOH + 4 I 2
+ CH 3 COONa + 3 H 2 O
(ii)
(b) (i)
(ii)
OR(a)
(b)
(c) Carboxylicacids do not give reactions of carbonyl groups as it enters into resonance with lone pair of -
(d)
(e)
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