Aldehydes and ketones are prepared from alcohols, alkenes, and alkynes via different reaction pathways. Alcohols are the most commonly used substrates for synthesizing aldehydes and ketones. The conversion of alcohol to aldehyde, which involves the oxidation process, depends on the class of the alcohol used and the strength of the oxidizing agent. For instance, primary alcohol will form an aldehyde when treated with a weak oxidizing agent; however, it gets over-oxidized to a carboxylic acid in...

Aldehydes are more reactive than carboxylic acids and hence, can get over-reduced to alcohol in the presence of strong reducing agents. Therefore, carboxylic acids are inefficient in preparing aldehydes using LAH.
Carboxylic acid derivatives like acid chlorides and esters are more easily reducible than the corresponding acids. The derivatives reduce in the presence of mild reducing agents to give aldehydes. Aldehydes can also be prepared by Rosenmund reduction, that is, the reduction of acid...

Some common aldehydes and ketones are popularly known by their common names used historically and predate the IUPAC nomenclature.
Common names of aldehydes are derived from the names of their corresponding acid. For instance, the two-carbon aldehyde–acetaldehyde derives its name from the corresponding acid–acetic acid. Similarly, formaldehyde derives its name from formic acid and benzaldehyde from benzoic acid.
Aliphatic ketones are named by suffixing the word “ketone” to the alphabetically...

In aldehydes, the hydrogen atom connected to the carbonyl carbon helps distinguish aldehydes from other carbonyl compounds using ¹H NMR spectroscopy. The closeness of aldehydic hydrogen to the electrophilic carbonyl carbon highly deshields the hydrogen atom causing its signal to appear around 10 ppm in the ¹H NMR spectra. α hydrogens split the aldehydic proton signal, which helps identify the number of α hydrogens in the molecule. For instance, one α hydrogen creates a doublet for an aldehydic...

Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.