Final answer:
Tertiary alcohols are more stable against oxidation but react quickly with Lucas reagent due to the stability of the tertiary carbocation formed during the reaction.
Step-by-step explanation:
The question is why tertiary alcohols react rapidly with Lucas reagent despite being more stable than other types of alcohols in terms of resistance to oxidation. Tertiary alcohols are more stable under oxidative conditions because the carbon atom attached to the OH group is bonded to other carbon atoms, rather than hydrogen atoms, making the formation of a carbon-to-oxygen double bond difficult during oxidation. However, this increased stability does not affect their reactivity with Lucas reagent, which is a test to differentiate alcohols based on their rate of reaction.
The different behavior of tertiary alcohols with Lucas reagent stems from their ability to form a more stable carbocation intermediate during the substitution process. The Lucas reagent, which is a mixture of zinc chloride and hydrochloric acid, promotes the replacement of the alcoholic hydroxyl group by a chloride ion through a carbocation intermediacy. Tertiary alcohols form more stable carbocations due to the inductive effect and hyperconjugation, which stabilize the positive charge. Consequently, tertiary alcohols react faster with Lucas reagent, unlike primary and secondary alcohols, which form less stable carbocations and hence react more slowly.