In the formation of organic compounds, which description corresponds to oxidation?

• A. Reduction: replacement of a hydrogen atom with a hydroxyl group
• B. Hydrolysis: addition of one or more water molecules
• C. Dehydration: removal of one or more hydrogen molecules
• D. Oxidation: replacement of a hydrogen atom with a hydroxyl group

Answer: (D)

Oxidation in organic chemistry means raising the oxidation state of a carbon center, often by attaching more electronegative atoms such as oxygen and by removing hydrogen. Replacing a hydrogen atom with a hydroxyl group is a classic oxidation step because you go from a C–H bond to a C–OH bond, which increases the carbon’s oxidation state due to the stronger influence of oxygen.

This description aligns with how oxidation is defined in practice, making it the best fit. Hydrolysis involves breaking bonds with water, not changing oxidation state; dehydration refers to removing water; reduction is the opposite process, involving gain of electrons or hydrogen.