Hydroxyl Group Defines Alcohols

Steps:

• Define alcohols as organic compounds with a hydroxyl group attached to a carbon atom.
• Identify the functional group in alcohols as -OH, based on their general formula R-OH.
• Examine the given choices to find the one matching -OH.
• Select option D as it directly represents the hydroxyl group.

Why D is correct:

• Alcohols are characterized by the -OH (hydroxyl) group, as per the IUPAC definition, which distinguishes them from other compounds.

Why the others are wrong:

• A. CH₃ is a methyl group, common in alkanes and alkyl chains, not specific to alcohols.
• B. COH represents the aldehyde group (-CHO), found in aldehydes like formaldehyde.
• C. NH is part of amines or amides, characteristic of nitrogen-containing compounds, not alcohols.

Final answer: D