Tuesday, February 5, 2008

IIT JEE Revision - Ch.27 Aldehydes and Ketones - Core Points


Aldehydes and Ketones:
Preparation, Physical properties and chemical properties
oxime and
hydrazone formation;
aldol condensation,
Perkin reaction;
Cannizzaro reaction;
haloform reaction and
nucleophilic addition reactions (Grignard addition);
Aldehydes contain carbonyl group C=O as functional group and the carbonyl atom carries at least one H atom.


In ketones, also carbonyl group C=O is the functional group. But the carbonyl carbon does not contain any H atoms, but it is attached to two alkyl or aryl groups.

Getting an aldehyde from methylbenzene - by oxidation

Getting ketone from alcohols - By oxidation of secondary alcohols

Aldehydes and ketones are polar molecules because the C=O bond has a
dipole moment:

• Their polarity makes aldehydes and ketones have higher boiling points than
alkenes of similar molecular weight.


Carbonyl groups in aldehydes and ketones may be oxidized to form
compounds at the next “oxidation level”, that of carboxylic acids

Addition Using Grignard Reagents• Primary, secondary and tertiary alcohols may be formed in the reactions of
aldehydes or ketones with Grignard reagents.


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