Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN) - Scottish Highers Chemistry - Question 16 - 2017

To determine which carbonyl compound reacts with hydrogen cyanide (HCN) to form the product shown, we need to analyze the structure of the target compound.

1. Analyze the Product Structure: The product has a hydroxyl group (–OH) and a cyano group (–CN), indicating it is a cyanohydrin. Therefore, the starting carbonyl compound must have a carbonyl group (C=O) and an additional hydrogen atom connected to the same carbon atom that bears the hydroxyl group in the product.

2. Consider Each Option:

   • Option A: Analyze if the carbonyl carbon can bond with HCN and retain a hydroxyl group.
   • Option B: Check the carbon number and positioning of functional groups.
   • Option C: Determine the placement of the C=O and potential HCN reaction.
   • Option D: Assess if this option can form the target compound upon addition of HCN.

3. Identify the Correct Option: According to the reaction mechanism of forming cyanohydrins, option A is the correct answer, as it provides the necessary carbon arrangement to result in the desired product after reacting with HCN.