Chemistry · Aldehydes and Ketones

The correct answer is HCHO (formaldehyde) because it is an aldehyde with a highly electrophilic carbonyl carbon. Aldehydes are generally more electrophilic than ketones because they have fewer electron-donating groups attached to the carbonyl carbon, which allows for greater reactivity towards nucleophiles. In contrast, the other options are less electrophilic due to the presence of electron-donating groups or additional steric hindrance:

• HCOOH (formic acid): Although it has a carbonyl group, the -OH group decreases its electrophilicity.
• CH₃COCH₃ (acetone): As a ketone, it has two methyl groups that donate electron density, reducing electrophilicity.
• CH₃COOH (acetic acid): The carbonyl is adjacent to a hydroxyl group, which also donates electron density, further decreasing electrophilicity.

Formic acid contains a carbonyl group, but the presence of the hydroxyl group (-OH) reduces its electrophilicity compared to aldehydes.

Formaldehyde is the simplest aldehyde and has a highly electrophilic carbonyl carbon due to the lack of steric hindrance and the absence of strong electron-donating groups.

Acetone is a ketone with two methyl groups that donate electron density, making its carbonyl carbon less electrophilic than that of aldehydes.

Acetic acid has a carbonyl group adjacent to a hydroxyl group, which reduces the electrophilicity of the carbonyl carbon due to intramolecular hydrogen bonding and electron donation from the -OH group.