Select Board & Class


Aldehydes, Ketones and Carboxylic Acids

Carbonyl Group – Nomenclature and Structure


In the IUPAC system, aliphatic carboxylic acids are named as follows:

  • By replacing the ending ‘− e’ in the name of the corresponding alkane with ‘− oic acid’

  • Carboxylic carbon is numbered one.

  • If more than one carboxyl groups are present, then the ending ‘− e’ of the alkane is retained.

  • The number of carboxyl groups is indicated by adding prefix, di, tri, etc. to the term ‘oic’.

The given table lists the common and IUPAC names and structures of some carboxylic acids.

Names and Structures of Some Carboxylic Acids


Common name

IUPAC name


Formic acid

Methanoic acid


Acetic acid

Ethanoic acid


Propionic acid

Propanoic acid


Butyric acid

Butanoic acid


Isobutyric acid

2-Methylpropanoic acid


Oxalic acid

Ethanedioic acid


Malonic acid

Propanedioic acid


Succinic acid

Butanedioic acid


Glutaric acid

Pentanedioic acid


Adipic acid

Hexanedioic acid


Propane-1, 2, 3-

tricarboxylic acid

Benzoic acid

Benzenecarboxylic acid

(Benzoic acid)

Phenylacetic acid

2-Phenylethanoic acid

Phthalic acid

Benzene-1, 2-dicarboxylic


Structure of Carboxyl Group

  • Carboxyl carbon is less electrophilic than carbonyl carbon because of resonance.

  • Bonds to the carboxyl carbon lie in one plane and are separated by about 120°.

Methods of Preparation of Carboxylic Acid

  • From primary alcohols

  • From aldehydes

Oxidising agents − HNO3, KMnO4, K2Cr2O7 and mild oxidising agents as well like Tollen’s reagent and Fehling’s reagent.

  • From alkyl benzenes

  • 1° and 2° alkyl benzene are oxidised in this manner.

  • Tertiary group is not affected.

  • From nitriles and amides

  • From Grignard reagents

  • From acyl halides

  • From acid anhydrides

  • From esters

  • Ester Carboxylic acid + Alcohol





Common Names of Aldehydes

  • Often called by their common names instead of IUPAC names

  • Derived from the common names of the carboxylic acids by replacing the ending ‘−ic’ of the acid with aldehyde

  • Location of the substituent in the carbon chain is indicated by the Greek letters α, β, γ, δ, etc.

  • Example:

Common Names of Ketones

  • Derived by naming two alkyl or aryl groups bonded to the carbonyl group

  • Locations of substituents are indicated by the Greek Letters, α, α′, β, β′, and so on 

  • The simplest dimethyl ketone is called acetone.

  • Alkyl phenyl ketones are usually named by adding the acyl group as prefix to phenone.


  • For open-chain aliphatic aldehydes and ketones, IUPAC names are derived from the names of the corresponding alkanes by replacing the ending ‘−e’ with ‘−al’ and ‘−one’ respectively.

  • In the case of aldehydes, the longest chain is numbered starting from the carbon of the aldehydic group.

  • In the case of ketones, the numbering begins from the end nearer to the carbonyl gro…

To view the complete topic, please

What are you looking for?