unknown functional group tests

bromine/CCl4: decolorization of the solution

alkenes

flame test: black, sooty smoke

aromaticity

beilstein test: green flame

halogens (except fluorine)

silver nitrate test: immediate precipitate

benzylic, allylic, and tertiary alkyl halides

silver nitrate test: precipitate with heat

primary and secondary alkyl halides

chromic acid test: immediate blue-green color

primary or secondary alcohols or aldehydes

lucas test: form precipitate within two min

benzylic, allylic, or tertiary alcohol

lucas test: form precipitate wafter ten min

secondary alcohol

ferric chloride test: red, blue, purple, green color

phenol

bromine-water test: disappearance of yellow coloration

phenol (aromatic compounds will give false positive)

2,4-dinitrophenylhydrazine (DNP) test: yellow precipitate

non-conjugated carbonyl of an aldehyde or ketone

2,4-dinitrophenylhydrazine (DNP) test: orange, red precipitate 

conjugated carbonyl of an aldehyde or ketone

tollens test: silver mirror

aldehyde

iodoform test: yellow precipitate

methyl ketone (ethanol and acetaldehyde will give false positives)

sodium bicarbonate test: bubbles

carboxylic acid

hinsberg test: soluble in NaOH

primary amine

hinsberg test: insoluble in NaOH and HCl

secondary amine

hinsberg test: insoluble in NaOH, soluble in HCl

tertiary amine

hydroxyl amine/ferric chloride test: red, purple coloration

ester (phenols give false positive, so use hydroxyl amine hydrochloride)

iron (II) hydroxide test: red-brown, brown precipitate

nitro group