How many of the following compounds will produce immediate turbidity with Lucas reagent (anhydrous + — Practical Organic Chemistry and Purification Chemistry Question
Question
How many of the following compounds will produce immediate turbidity with Lucas reagent (anhydrous $ZnCl_2$ + conc. $HCl$) at room temperature? List: 2-Methylpropan-2-ol, 2-Methylbutan-2-ol, Propan-2-ol, Ethanol, 1-Methylcyclohexanol, Butan-1-ol.
💡 Solution & Explanation
Lucas reagent differentiates alcohols based on the stability of the intermediate carbocation. Tertiary ($3^\circ$) alcohols form stable tertiary carbocations and undergo $S_N1$ reaction to form insoluble alkyl chlorides almost immediately. 2-Methylpropan-2-ol, 2-Methylbutan-2-ol, and 1-Methylcyclohexanol are $3^\circ$ alcohols (3 compounds). Propan-2-ol ($2^\circ$) takes minutes. Ethanol and Butan-1-ol ($1^\circ$) show no reaction at room temperature.