Which of the following compounds is an intermediate in the preparation of phenol via the oleum fusio — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Benzene is first sulphonated using oleum (fuming sulphuric acid) to form benzenesulphonic acid. This intermediate is then fused with molten $NaOH$ to yield sodium phenoxide, which gives phenol upon acidification.