NEET Chemistry Notes Aldehydes, Ketones and Carboxylic Acids – Aldehydes and Ketones
Aldehydes and Ketones
Aldehydes and Ketones
The organic compounds containing carbon-oxygen double bond, 
group are called carbonyl compounds. These compounds are widely spread both in plant and animal kingdom and they play an important role in biological processes.
Nomenclature
Aldehydes and ketones are functional isomers.
According to IUPAC nomenclature system, name of aldehyde is obtained by replacing the terminal ‘e’ of the corresponding alkane by the suffix ‘al’.
Name of a ketone is obtained by replacing the terminal ‘e’ of the corresponding alkane by the suffix ‘one’.
Nature of Carbonyl Group
In carbonyl group, n-electron cloud is displaced towards more electronegative oxygen atom thus, causing polarisation of the bond so that carbon is partially positive and oxygen is partially negative.
In resonance terms, electron delocalisation in the carbonyl group is represented by contributions from two principal resonance forms.
Preparation of Aldehydes and Ketones
There are several methods from which aldehydes as well as ketones can be synthesised. These methods are as follows:
- By Ozonolysis of Alkenes
- By Hydration of Alkynes
Acetylene on hydration gives acetaldehyde and other alkynes on hydration give ketones.
- From Grignard Reagent
HCN when reacts with Grignard reagent and then subjected to hydrolysis, gives aldehydes while RCN gives ketone.
