Back to Directory
NEET CHEMISTRYEasy

Which one of the following alcohols reacts instantaneously with Lucas reagent?

A

Option 1 (Structure Missing)

B

Option 2 (Structure Missing)

C

Option 3 (Structure Missing - Likely a Tertiary Alcohol)

D

CH3-CH2-CH2-CH2OH (n-Butyl alcohol)

Step-by-Step Solution

The reaction of alcohols with Lucas reagent (concentrated HCl and anhydrous ZnCl2ZnCl_2) proceeds via an SN1S_N1 mechanism involving a carbocation intermediate. The rate of reaction depends on the stability of the carbocation formed.

  1. Reactivity Order: Tertiary (33^{\circ}) > Secondary (22^{\circ}) > Primary (11^{\circ}).
  2. Observations:
  • Tertiary Alcohols: Form highly stable tertiary carbocations and react instantaneously to form alkyl halides, producing immediate turbidity.
  • Secondary Alcohols: React within approximately 5 minutes.
  • Primary Alcohols: Do not react appreciably at room temperature (turbidity appears only upon heating).

Option 4 (CH3CH2CH2CH2OHCH_3CH_2CH_2CH_2OH) is a primary alcohol and will not react instantaneously. Therefore, the correct option (Option 3) must represent a tertiary alcohol (e.g., 2-Methylpropan-2-ol).

Practice Mode Available

Master this Topic on Sushrut

Join thousands of students and practice with AI-generated mock tests.

Get Started