Orgo Lab Functional Group tests

Bromine/CCl4 Test

Test for presence of alkenes. Br2 is an orange/brown color, turns colorless as it is added across double bond. (+) result is color change, (-) result is no color change.

Flame Test

For aromatic compounds. Black sooty smoke, indicates aromatic. Rapid = high oxygen content. Combustion w/ sparks = nitrogen. Color of flame indicates oxygen content and saturation.

Beilstein Test

Test for halides. Heated copper wire + sample is put over flame. Green flash is positive result for containing a halide.

Silver Nitrate Test

For halide structure. Undergoes SN1 reaction with AgNO3. Immediate precipitate is 3 or benzylic halide, slow precipitate is 1 or 2, no precipitate is aryl or akenyl halide.

Lucas Test

For alcohol structure. Adds ZnCl2, HCl, undergoes SN1 reaction. 3 alcohol reacts fastest, 1 alcohol does not react at all.

Chromic Acid Test

For presence of alcohols. Add H2CrO4, negative test is 3 alcohol, positive is 1 or 2 (aldehydes give false positive)

Ferric Chloride Test

For phenols. Red, blue, purple or green color indicates presence of phenol.

Bromine-Water Test

Presence of a phenol. Disappearance of yellow indicates bromine has been consumed, and phenol is present. Other activated aromatic compounds may give false positive.

2,4-DNP Test

For aldehydes and Ketones. Red, orange, or yellow precipitate indicates presence of either aldehyde or ketone. Yellow = not conjugated, Orange = conjugated, reddish = extended conjugation, aromatic

tollens test

Distinguishes aldehydes and ketones. Adds AgNO3, NH4OH, forms silver precipitate with aldehydes. Ketones produce no reaction.

Chromic Acid For Aldehydes

Add chromic acid. Green is positive, indicates aldehyde. Orange is negative, indicates ketone

Iodoform test

Test for methyl ketones. Pale yellow indicates presence of a methyl ketone, creates iodoform byproduct (yellow)

Hydroxylamine/Ferric Chloride test

For esters. Deep red/ purple color indicates presence of ester.

Iron(II) hydroxide test

For presence of Nitro compounds. The presence of a red-brown or brown precipitate within 1 minute constitutes a positive test for nitro groups.

Hinsberg Test

For structure of amines. Primary amines are soluble, precipitate after second fraction. Secondary amines are insoluble after first fraction. Tertiary amines are soluble in fraction A.