Alcohols are the compounds containing hydroxyl group attached to the alkyl group, whereas phenols are hydroxyl derivatives of aromatic hydrocarbons in which hydroxyl group is directly attached to carbon atom of aromatic ring. Alcohols are versatile compounds and can behave both as nucleophiles as well as electrophiles.
Phenols, too are reactive compounds and are known to undergo reactions on : phenolic group, benzene ring as well as various other name reactions like Reimer-Tiemann reaction, Kolbe's reaction etc.

The correct answer is option 3.

The conversion of phenol to 1,4-benzoquinone is a commonly used reaction in organic chemistry, known as the oxidation of phenol. The oxidizing agent used is typically potassium dichromate \((K_2Cr_2O_7)\) or sodium dichromate \((Na_2Cr_2O_7)\) in the presence of an acidic medium, like sulfuric acid \((H_2SO_4)\). This process involves the oxidation of the phenolic group to a quinone structure. The reaction will be as follows:

Here, phenol is oxidized to 1,4-benzoquinone.

Step-by-Step Process:

Oxidation of Phenol: The oxidizing agent, such as \(K_2Cr_2O_7\), removes two hydrogen atoms from the phenolic group and the para position, leading to the formation of a double bond between the oxygen atom and the carbon atom. This generates a conjugated structure with alternating single and double bonds (the quinone structure).

Formation of 1,4-Benzoquinone: The product formed is 1,4-benzoquinone, where the oxygen atoms are double-bonded to the 1st and 4th carbon atoms of the aromatic ring.

Summary:

Phenol can be oxidized to 1,4-benzoquinone using oxidizing agents like potassium dichromate in an acidic medium. The reaction removes hydrogen atoms and forms a conjugated system with alternating double bonds, resulting in 1,4-benzoquinone.