Identification of an organic unknown
Aim
In this piece of coursework I will be outlining a sequence of simple chemical tests to use to identify 8 different functional groups.
These functional groups I will be finding are, Alkene, primary alcohol, tertiary alcohol, aldehyde, ketone, carboxylic acid, ester and phenol.
I will be explaining the tests, the observations and the safety of each test/functional group.
Wet Tests
Bromine water
In the presence of an Alkene, the bromine water will turn the unknown from orange to colourless. C2H4(L) + Br2(L) C2H4Br2(L)
In the presence of a phenol group, a white precipitate will be formed when bromine water is added.7
Phenol(L) + 3Br2(L) 2, 4, 6-tribromophenol(L) + 3HBr(L)
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2, 4 DPNH/Brady’s reagent
Add a few drops to Brady's reagent (2, 4-dinitrophenylhydrazine solution) to the unknown. Brady’s reagent detects the carbonyl function of an aldehyde and ketone. Yellow/orange precipitate forms with aldehyde or ketone.
