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#12th class organic chemistry
Chapter: Alcohol, Phenol, Ether
PYQ.

Q.Write The Lucas Test of Alcohol?
1) Primary Alcohol
2) Secondary Alcohol
3) Tertiary Alcohol

By Anant Kausale sir
Dr.A.P.J.Abdul Kalam Research Centre.

The Lucas reagent is a chemical mixture primarily used to differentiate between primary, secondary, and tertiary alcohols. It is composed of anhydrous zinc chloride (ZnCl2) dissolved in concentrated hydrochloric acid (HCl). The reaction with alcohols results in the formation of alkyl chlorides, and the rate at which this reaction occurs distinguishes between the different types of alcohols.

Components and Preparation:

Anhydrous Zinc Chloride (ZnCl2):

This acts as a Lewis acid, which facilitates the reaction by forming a bond with the oxygen atom in the alcohol, making the carbon more susceptible to nucleophilic attack.

Concentrated Hydrochloric Acid (HCl):
The source of chloride ions (Cl-) which react with the carbocation formed after the alcohol is protonated, forming the alkyl chloride.

Reaction with Alcohols:
Tertiary Alcohols: React immediately with Lucas reagent, forming a cloudy solution within a few minutes due to the precipitation of the alkyl chloride.

Secondary Alcohols: React slowly, forming a cloudy solution within 5-15 minutes.

Primary Alcohols: Generally do not react at room temperature and remain clear.