(i) CH2 = CH − CH2OH CH2 = CH − CHO
Primary alcohol vapours when passed over heated Cu at 573K, dehydrogenation takes place to give aldehyde.
(ii) CH3− COOH + NH3 ¾ CH3COONH4 CH3− CONH2
Carboxylic acid reacts with ammonia to give ammonium salt which on further heating gives amide.
(i) Aldehydes are more reactive towards nucleophilic addition reaction than ketones due to steric and electronic reasons. Sterically, presence of 2 relatively large groups on ketone hinders the approach of nucleophile to carbonyl carbon as compared to that of only one group on carbonyl carbon. Electronically, in ketones 2 alkyl groups which are electron releasing decreases the electrophilicity of carbon.
But aromatic ketones are more reactive than aliphatic ketones because phenyl group is less electron releasing than alkyl group. Thus, it does not decrease the electrophilicity of carbonyl carbon as compared to that of alkyl carbon.
Therefore, the order of reactivity towards nucleophilic substitution reaction is CH3COCH3 < C6H5COCH3 < CH3CHO.
(ii) The presence of EWG i.e. Cl and F increases the acidity of carboxylic acids by stabilizing the negative charge of conjugate base by –I effect. And –I effect of F is greater than that of Cl.
Whereas presence of EDG i.e. –CH3 decreases the acidity by destabilizing the negative charge of conjugate base by +I effect.
Therefore, order of acidic character:
F − CH2− COOH> Cl − CH2− COOH> CH3 − COOH
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