When acetaldehyde Is treated with dilute NaOH the following reaction is observed. 2 CH 3 - CHO → dil . NaOH CH 3 - CH | OH - CH 2 - CHO What are the functional groups in the product?

There are two functional groups in the product, which are aldehyde and an alcohol i.e. - CHO and - OH respectively. Aldol condensation occurs in aldehydes having α - hydrogen with a dilute base to give β - hydroxy aldehydes called aldols. This reaction is most commonly known as aldol condensation.

Write short notes on the stephen reaction.

Alkyl nitriles undergo reduction with the help of tin (II) chloride and hydrochloric acid and form an intermediate imine salt which undergoes hydrolysis with water, giving the final result as aldehydes. R − CN + 2 [ H ] → SnCl 2 / dil . HCl R − CH = NHHCl → H 2 O R − CHO + NH 4 Cl

Explain the following reaction: Cannizzaro reaction

Cannizzaro's reaction: The self oxidation-reduction (disproportionation) reaction of aldehydes which do not have α -hydrogen atom, on treatment with concentrated alkali is known as the Cannizzaro's reaction. In this reaction, two molecules of aldehydes participate where one is reduced to alcohol and the other is oxidised to carboxylic acid. For example, when methanal is treated with concentrated potassium hydroxide, methanol and potassium methanoate are produced. 2 HCHO → Con . KOH CH 3 OH + HCOOK