Which oxidizing agent is used in the qualitative test for alcohol oxidation?

Which oxidizing agent is used in the qualitative test for alcohol oxidation?

• A. Sodium hydroxide
• B. Potassium permanganate
• C. Oxygen
• D. Acidified potassium dichromate

Answer: (D)

The test relies on acidified potassium dichromate as the oxidizing agent. In acidic solution, the orange Cr(VI) in the dichromate is reduced to Cr(III), which turns the solution green as the alcohol is oxidized. This visible color change is the hallmark of the qualitative oxidation test: primary alcohols are oxidized first to aldehydes and can be further oxidized to carboxylic acids, while secondary alcohols are oxidized to ketones. Sodium hydroxide is not an oxidizer, so it doesn’t drive the oxidation. Oxygen can oxidize some substances but isn’t used in this standard qualitative test. Potassium permanganate can also oxidize alcohols, but the classic qualitative test for alcohol oxidation specifically uses acidified dichromate, giving the characteristic orange-to-green change.

The test relies on acidified potassium dichromate as the oxidizing agent. In acidic solution, the orange Cr(VI) in the dichromate is reduced to Cr(III), which turns the solution green as the alcohol is oxidized. This visible color change is the hallmark of the qualitative oxidation test: primary alcohols are oxidized first to aldehydes and can be further oxidized to carboxylic acids, while secondary alcohols are oxidized to ketones. Sodium hydroxide is not an oxidizer, so it doesn’t drive the oxidation. Oxygen can oxidize some substances but isn’t used in this standard qualitative test. Potassium permanganate can also oxidize alcohols, but the classic qualitative test for alcohol oxidation specifically uses acidified dichromate, giving the characteristic orange-to-green change.