Alcohol on refluxing with Cr2O7 gives Carboxylic acid.

Alcohol can be oxidized to form various functional groups depending on the oxidizing agent used. When alcohol is refluxed with Cr2O7 (chromic acid), it undergoes oxidation to form carboxylic acid.

Here is the detailed explanation:

1. Oxidation of Alcohol
Alcohol undergoes oxidation when it reacts with an oxidizing agent. In the case of Cr2O7, it acts as a strong oxidizing agent and can oxidize primary and secondary alcohols to carboxylic acids and ketones, respectively.

2. Acidic Conditions
During the refluxing process, Cr2O7 is usually mixed with an acidic solution such as concentrated sulfuric acid (H2SO4). This acidic environment helps in the conversion of alcohol to carboxylic acid by protonating the alcohol molecule. The protonated alcohol then reacts with the oxidizing agent.

3. Formation of Chromate Ester
Initially, the alcohol reacts with Cr2O7 to form a chromate ester intermediate. In this step, one of the oxygen atoms from the Cr2O7 molecule attacks the carbon atom of the alcohol, forming a bond between them. This results in the formation of a chromate ester.

4. Hydrolysis of Chromate Ester
The chromate ester is unstable and undergoes hydrolysis in the presence of water. Hydrolysis breaks down the ester bond, releasing the carboxylic acid as the final product. This hydrolysis step is usually carried out after the refluxing process by adding water to the reaction mixture.

Overall, the refluxing of alcohol with Cr2O7 in acidic conditions leads to the oxidation of alcohol to carboxylic acid. The reaction proceeds through the formation of a chromate ester intermediate, which is subsequently hydrolyzed to yield the carboxylic acid.