Qualitative Tests for Alcohols

Qualitative Tests for Alcohols

Contents

• Qualitative tests for alcohols

Learning Objectives

At the end of this lecture, student will be able to

• Explain the qualitative tests for alcohols

Qualitative tests for Alcohols

• Alcohols are compounds in which the hydroxyl group (-OH) is linked to aliphatic carbon chain or in the side chain of an organic compound

• Further classified as primary (1°), secondary (2°) and tertiary (3°) according to the –OH group is attached to the primary, secondary and tertiary carbon atoms respectively

• Sodium metal test

• Alcohols react with active metals like sodium and liberate hydrogen gas that can be observed in the form of effervescence

Jones Oxidation for Primary and Secondary Alcohols

• Jones reagent (chromic acid in sulfuric acid)

• Formation of green color within 15 sec- primary or secondary alcohol

• Tertiary alcohols- remain orange in color

Lucas Test for Secondary and Tertiary Alcohols

• Lucas reagent- Zinc chloride in HCl

• Formation of alkyl chloride as insoluble layer or emulsion

• 3o alcohols: immediate to 2-3 minutes

• 2o alcohols: 5 -10 minutes

• 1o alcohols: no reaction

Summary

• Jones Oxidation for Primary and Secondary Alcohols

• Lucas Test for Secondary and Tertiary Alcohols

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