Solubility and Classification Tests

2,4-Dinitrophenylhydrazine (2,4-DNP) test

A test positive for aldehydes and ketones; negative for alcohols and esters.

Independence during exam

Work independently during the practical exam; no talking or questions allowed.

Solubility and Classification Tests

Tests to determine the solubility and classify organic compounds.

Glass Waste Container

Container for discarding empty & H2O-rinsed used test tubes & pipets.

Jones Reagent

Chromic acid in sulfuric acid used for oxidizing alcohols and aldehydes.

Cerium (IV) Nitrate Test

Test that indicates a positive result by a color change from yellow to orange-red.

Lucas Test

Distinguishes between water-soluble 1o, 2o, and 3o alcohols based on cloudiness formation.

Iodoform Test

Test for 2-alkanols that produces a bright yellow precipitate of iodoform.

Aldehydes

Compounds that can be oxidized by Jones reagent and give a positive test.

2,4-Dinitrophenylhydrazine Test

Test that reacts with most aldehydes and ketones to form bright yellow to dark red hydrazones.

Cloudiness in Lucas Test

3o alcohols show cloudiness instantly; 2o alcohols take longer, and 1o alcohols take hours.

Primary Alcohols

Oxidized by Jones reagent, giving a positive test.

Secondary Alcohols

Oxidized by Jones reagent, giving a positive test.

Tertiary Alcohols

Not oxidized by Jones reagent, giving a negative test.

Color Change in Cerium Test

Yellow to orange-red indicates a positive test for alcohols.

Esters and Alcohols Reaction

Do not react with 2,4-dinitrophenylhydrazine; yellow-orange color persists.

Amines Classification Test

Test water-soluble unknowns with litmus paper for amine functionality.

Testing Water-Insoluble Amines

Apply a small amount of the unknown directly to water-wet litmus paper.

Carboxylic Acids Classification Test

Solubility in 5% NaHCO3 with CO2 gas evolution indicates a carboxyl group.

Wet-Litmus Test for Carboxylic Acids

Apply a small amount of the unknown to water-wet litmus paper.

Phenols Solubility Test

Phenols are soluble in 5% NaOH and insoluble in 5% NaHCO3.

Decolorization of Br2/CH2Cl2 Solution

Positive test if more than 5 drops of bromine solution are needed to maintain color.

Testing for Acidic Vapor

Test vapor from bromination with litmus paper to confirm presence of phenol.

Waste Disposal for Halogenated Tests

Discard contents in a 'HALOGENATED LIQUID ORGANIC WASTE' container.

Prolonged Exposure to Neutral Compounds

Litmus paper can change color; record results immediately and discard paper.

Crushing Solid Unknowns

Crush solid unknowns to a powder before applying to litmus paper.

Adding HCl or H2SO4 to Carboxylic Acids

Observe precipitate or oil formation when added to 5% NaHCO3 solution.