Reduction of the carbonyl group to CH₂ occurs with zinc-amalgam and concentrated hydrochloric acid (Clemmensen reduction) or hydrazine followed by heating with sodium or potassium hydroxide in ethylene glycol (Wolff-Kishner reduction).

Aldehydes are reduced to primary alcohols, and ketones to secondary alcohols, using sodium borohydride (NaBH₄), lithium aluminium hydride (LiAlH₄), or catalytic hydrogenation.

Aldehydes are more reactive due to both steric and electronic reasons. Sterically, the hindered approach of nucleophile to the carbonyl carbon is less in aldehydes. Electronically, aldehydes are more reactive because two alkyl groups in ketones reduce the electrophilicity of ...

Aldehydes and ketones are commonly prepared by the oxidation of primary and secondary alcohols, respectively.

Carbonyl compounds have a planar structure with a π-bond, leading to substantial dipole moments. The high polarity is explained by resonance, involving neutral (A) and dipolar (B) structures, contributing to the overall dipole moment of carbonyl compounds.

The double bond is polarized due to the higher electronegativity of oxygen. The carbonyl carbon acts as an electrophilic (Lewis acid), and the carbonyl oxygen serves as a nucleophilic (Lewis base) center.

Nucleophilic addition involves attack by a nucleophile on the electrophilic carbon of the carbonyl group, changing the hybridization of the carbonyl carbon from sp² to sp³. This process forms a tetrahedral alkoxide intermediate that captures a proton to yield the ...

Aldehydes and ketones undergo nucleophilic addition reactions, whereas alkenes experience electrophilic addition reactions.

Lower aldehydes and ketones (e.g., methanal, ethanal, propanone) are miscible with water due to hydrogen bonding. However, solubility decreases with increasing alkyl chain length.

The absence of intermolecular hydrogen bonding in aldehydes and ketones contributes to their lower boiling points compared to alcohols. Alcohols exhibit stronger intermolecular forces due to hydrogen bonding.