Skip to content
Question 75 of 76

Q.Propan-2-ol on reaction with anhydrous ZnCl2ZnCl_2 and concentrated HCl gives ________.

(a) 1-chloropropane
(b) Ethyl chloride
(c) 2-chloro-2-methyl propane
(d) 2-chloropropane
Puducherry TnboardTamil Nadu HSC (DGE) Board 2026MCQ· 1mImportance★★★★★
99% · 75/76 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

The Lucas reagent (anhydrous ZnCl2ZnCl_2 + concentrated HCl) converts an alcohol to the corresponding alkyl chloride via an SN1S_N1 mechanism through a carbocation intermediate; propan-2-ol, a secondary alcohol, forms a moderately stable secondary carbocation and reacts within a few minutes to give the secondary chloride, retaining its original carbon skeleton.

The Lucas test/reaction distinguishes primary, secondary, and tertiary alcohols by their differing rates of reaction (via SN1S_N1) with the Lucas reagent, based on carbocation stability. Propan-2-ol, (CH3)2CHOH(CH_3)_2CHOH, being a secondary alcohol, is protonated by the HCl, loses water to form a relatively stable secondary carbocation, (CH3)2CH+(CH_3)_2CH^+, which is then quickly captured by chloride ion: (CH3)2CHOH+HCl→anhyd. ZnCl2(CH3)2CHCl (2-chloropropane)+H2O(CH_3)_2CHOH + HCl \xrightarrow{anhyd.\ ZnCl_2} (CH_3)_2CHCl\ (\text{2-chloropropane}) + H_2O Since the mechanism proceeds through the same carbon skeleton (via the carbocation at C-2), the product retains the same connectivity as the starting alcohol — 2-chlorop …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.