When acetonitrile is hydrolysed partially with cold concentrated HCl it forms acetamide.

On further hydrolysis acetamide may give either CH₃COOH (acetic acid) or its salt.

In the Cannizzaro reaction, two moles of carbonyl compounds having no α-hydrogen atom when treated with strong alkali undergo, redox or disproportionation reaction.

Mechanism :First of all base OH–acts as a nucleophileand attack other one of carbonyl compound to generate ahydroxy alkoxide ion which acts as a hydride iondonor to the other molecule of carbonyl compounds. In the final step there is a exchange of proton from acid to alkoxideion to get stable product.

Formaldehyde on reaction with ammonia forms a crystalline compound, hexamethylene tetramine.

Benzaldehyde forms cinnamic acid as follows.

Cl₂ does not give acid chloride on treating it with acarboxylic acid.

While PCl₃, PCl₅ and SOCl₂ gives nucleophilic substitution reaction with carboxylic acid (Cl^–replaces OH^–group of– COOH)

Aldol condensation involves an aldehyde or ketone having an α–hydrogen atom. This type of condensationoccurs in presence of dilute base (i.e., dil NaOH).Only CH₃COCH₃ will give aldol condensation(Both HCHO and C₆ H₅CHO lack α-hydrogen).

We can distinguish between formic acid and acetic acid by their action on Fehling’s solution. Formic acid gives ared ppt of cuprous oxide but acetic acid does not give red ppt.