Which substance is commonly used for the oxidation of alcohols?

The oxidation of alcohols involves the conversion of the alcohol functional group into a carbonyl group or a carboxylic acid, depending on the conditions and the type of alcohol used. Hot copper (II) oxide and acidified dichromate (VI) solution are both effective oxidizing agents for this process.

Hot copper (II) oxide can oxidize primary and secondary alcohols, leading to aldehydes or ketones, respectively. It acts as a dehydrating agent and is suitable for high-temperature reactions where complete oxidation is desired.

Acidified dichromate (VI) solution (often in the form of potassium dichromate in sulfuric acid) is another well-known oxidizing agent for alcohols. It operates under conditions that favor safe oxidation, and it can selectively oxidize primary alcohols to aldehydes, which can further be oxidized to carboxylic acids, and secondary alcohols to ketones.

Both of these reagents effectively facilitate the oxidation of alcohols, making option C the correct answer.