Provide an example of the nucleophilic addition of different aldehydes and ketones.

The nucleophilic addition of aldehydes and ketones involves the addition of a nucleophile to the carbonyl group.

One example of nucleophilic addition is the reaction between formaldehyde and hydrogen cyanide. The nucleophile, cyanide ion, attacks the electrophilic carbon of the carbonyl group, forming a tetrahedral intermediate. The intermediate then collapses, forming a new carbon-nitrogen bond and a hydroxyl group. This reaction is known as the cyanohydrin reaction and is used in the synthesis of α-hydroxy acids and amino acids.

Another example is the reaction between acetone and sodium bisulfite. The nucleophile, bisulfite ion, attacks the carbonyl group, forming a sulfonic acid intermediate. The intermediate then undergoes a dehydration reaction, forming a sulfonic acid ester. This reaction is used in the purification of aldehydes and ketones.

A third example is the reaction between benzaldehyde and phenylhydrazine. The nucleophile, phenylhydrazine, attacks the carbonyl group, forming a hydrazone intermediate. The intermediate then undergoes a dehydration reaction, forming a stable hydrazone. This reaction is used in the identification of aldehydes and ketones.

Overall, nucleophilic addition is an important reaction in the chemistry of aldehydes and ketones. It allows for the formation of new carbon-nitrogen and carbon-oxygen bonds, leading to the synthesis of a wide range of organic compounds.