CBSE Class 12 Chemistry 2022 Term 2 Delhi Set 3

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Question : 9
Total: 12
(a) What happens when
(i) Propanone is is treated with CH3MgBr and then hydrolysed?
(ii) Ethanal is treated with excess ethanol and acid?
(iii) Methanal undergoes Cannizzaro reaction?
(b) Write the main product in the following reaction?
(i) 2CH3COCl+(CH3)2Cd
(ii) CH3CH2CHO
Zn(Hg) Conc HCl

Solution:  
(a) (i) When propanone reacts with ethyl magnesium bromide (Grignard's reagent) and hydrolysed, it forms aldehyde.
(CH3)2CO+H3CCH2MgBr
H2O
CH2CH3
|
(CH3)2COH+Mg(OH)Br

(ii) When ethanal reacts with excess ethanol and acid gives acetal.

(iii) Methanal will undergo Cannizzaro reaction as it possesses α-hydrogen to form methanol.

OR
(b) (i)
2CH3COCl
Propanone
+
(CH3)2Cd
CadmiumChloride
2CH3COCH3
+CdCl2
(ii) CH3CH2CHO
ZnHg
Conc. HCl
CH3CH2CH3
Propane

(iii)
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