Which compound is oxidized in air to form colored quinones?
Phenol (C₆H₅OH) undergoes oxidation in air to form quinones and other colored compounds, which may impart a yellowish or brownish color.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Preparation of Phenols and Ethers - Williamson and Other Methods