What happens when two moles of benzaldehyde reacts with potassium cyanide followed by oxidation?

Benzil

The correct answer is option 2. Benzil.

When two moles of benzaldehyde react with potassium cyanide (KCN) followed by oxidation, the product formed is benzil.

The reaction between benzaldehyde and KCN leads to the formation of a cyanohydrin intermediate known as benzoin. This is achieved through a nucleophilic addition reaction, where the cyanide ion attacks the carbonyl carbon of benzaldehyde, followed by proton transfer and subsequent dehydration. Benzoin can be further oxidized to Benzil by mild oxidation agents such as nitric acid (HNO₃) or chromic acid (H₂CrO₄) or nascent oxygen.

When two moles of benzaldehyde react with potassium cyanide followed by oxidation, the product formed is benzil. Therefore, the correct answer is Benzil.