Aldehyde

RCHO is the general formula for aldehydes, where R stands for an alkyl group or a hydrogen atom. The carbonyl group is joined to either an alkyl group or a hydrogen atom at the end of the carbon chain. The carbon atom in the carbonyl group has a trigonal planar shape and is sp² hybridized.

Structure of Aldehyde

The structural formula of the Aldehyde is shown in the image below,

Aldehyde Properties

Aldehydes have unique chemical and physical characteristics. They are polar solvents like water-soluble, have a distinctively pungent smell, and have relatively low boiling temperatures in comparison to other organic compounds. Moreover, aldehydes are capable of a wide range of chemical processes, including nucleophilic addition, oxidation, and reduction.

Reactions of Aldehydes

Many chemical processes, such as nucleophilic addition, oxidation, and reduction, are possible with aldehydes.

Nucleophilic Addition

Aldehydes can engage in nucleophilic addition processes and are very reactive to nucleophiles. A nucleophile attacks the carbonyl group, which causes the creation of a new carbon-carbon bond. For instance, formaldehyde and ammonia can combine to create a primary amine.

Oxidation

Aldehydes can be oxidised to produce either pure carboxylic acids or a combination of alcohols and carboxylic acids. Aldehydes are often oxidised using the reagents potassium permanganate (KMnO₄), chromic acid (H₂CrO₄), and silver nitrate (AgNO₃).

Reduction

With reducing agents such as sodium borohydride (NaBH₄) or lithium aluminium hydride, aldehydes can be converted to primary alcohols (LiAlH₄). A new carbon-hydrogen bond is created when the carbonyl group is reduced to a hydroxyl group (-OH).

Applications of Aldehydes

Aldehydes have important applications in various industries such as,

• Production of plastics, dyes, and perfumes. 
• Formaldehyde, the simplest aldehyde, is widely used as a disinfectant and preservative.

A carbonyl group (-C=O) is found at the end of a carbon chain, which distinguishes aldehydes from other organic molecules. They are often present in nature and have significant uses across several sectors. In this assignment, the structure, characteristics, and reactivity of aldehydes will be covered.