Which alcohol forms a yellow precipitate with I₂ and NaOH only after oxidation?
Ethanol (CH₃CH₂OH) oxidizes to acetaldehyde, which has a CH₃CO- group and gives a yellow iodoform precipitate with I₂ and NaOH.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Preparation of Alcohols - from Alkenes Haloalkanes Carbonyls Grignard