Question

Why do tertiary alcohols react faster with lucas reagent?

Answer 1

Lucas reagent =HCl + anhydrous ZnCl2.

Alcohols react with Lucas reagent to form an insoluble alkyl halide

Reaction proceeds via SN1 mechanism which depends on carbocation stability.

As tertiary alcohol has 3 OH group, the stability of carbocations is as follows: Tertiary>Secondary>Primary.

Tertiary alcohols react almost immediately as they form tertiary carbocations which are the most stable. Turbidity is observed in seconds.

Secondary alcohols form white turbidity after about 5 minutes as the secondary carbocation is comparatively less stable.

The primary carbocation being the least stable react very slowly and primary alcohols take a lot of time to show turbidity.