CBSE Class 12 Chemistry 2017 Outside Delhi Set 1 Solved Paper

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Question : 26
Total: 26
(a) Write the product (s) in the following reactions:
(iii) CH3−CH=CH−CN‌
(a)‌DIBAL−H
─────▸
(b)H2O

(b) Give simple chemical tests to distinguish between the following pairs of compounds :
(i) Butanal and Butan-2-one
(ii) Benzoic acid and Phenol
OR
(a) Write the reactions involved in the following :
(i) Etard reaction
(ii) Stephen reduction
(b) How will you convert the following in not more than two steps :
(i) Benzoic acid to benzaldehyde
(ii) Acetophenone to benzoic acid
(iii) Ethanoic acid to 2-hydroxyethanoic acid
Solution:  
(iii) CH3−CH=CH−CHO
(b) (i) Tollen's reagent test : Add ammoniacal solution of silver nitrate (Tollen's reagent) in both the solutions. Butanal gives silver mirror whereas Butan-2-one does not.
(ii) Add neutral FeCl3 in both the solutions, phenol forms violet colour but benzoic acid does not.
OR(a) (i) Etard reaction
(ii) Stephen reaction
‌RCN+SnCl2+HCl→RCH =NH‌
H3O+
───▸
‌RCHO

OR
‌RCN‌
(i)SnCl2+HCl
─────▸
(ii)H3O+
‌RCHO



(iii) CH3‌COOH‌
Cl2∕p
───▸
‌
CH2
|
Cl
‌COOH
KOH(Aq)
───▸
CH2
|
OH
‌COOH
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