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CBSE Class 12 Chemistry 2020 Delhi Set 1 Solved Paper

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Question : 36 of 37
 
Marks: +1, -0
(a) Write the products formed when benzaldehyde reacts with the following reagents :
(i) CH3CHO in presence of dilute NaOH

(iii)Conc. NaOH
(b) Distinguish between following:
(i) CH3−CH=CH−CO−CH3 and CH3−CH2 −CO−CH=CH2
(ii) Benzaldehyde andBenzoic acid
OR
(a) Write the final products in the following:
(iii) CH2=CH−CH2−CN──────▸ (b) H3O+ (a) DIBAL−H
(b) Arrange the following in the increasing order of their reactivitytowards nucleophilic addition reaction:
(c) Draw the structure of 2, 4 DNP derivative of acetaldehyde.
Solution:
(a)
(b) (i) CH3−CH=CH−CO−CH3 gives iodoform test while CH3−CH2−CO−CH=CH2 does not give.
CH3−CH=CH−C∥O−CH3 +3NaOI→CH3IYellowppt.+2NaOH +CH3−CH=CHCOONa
CH3CHCOCH=CH2+3NaOI→ No ppt
(ii) ● Benzaldehyde reacts with tollen's reagent to form silver mirror. Benzoic acid does not give this reaction.

● With NaHCO3 benzaldehyde does not react while benzoic acid produces brisk effervescences.
OR
(a)

(iii) CH2=CH−CH2−CN──────▸ (b) H3O+ (a) DIBAL−H CH2=CH−CH2−C∥O−H
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