Several qualitative tests can detect the presence of phenol or phenolic compounds:
Ferric Chloride Test:
Phenols form colored complexes (violet, blue, green) with FeCl₃.
Positive Test: Appearance of color indicates phenols.
Bromine Water Test:
Phenols react with bromine to form a white precipitate of tribromophenol.
Positive Test: Decolorization and white precipitate indicate phenols.
Millon’s Test:
Phenols react with Millon’s reagent to form a red precipitate.
Positive Test: Formation of red precipitate indicates phenols.
Lieben's Iodoform Test:
Phenols react with iodine and NaOH to form a yellow precipitate of iodoform.
Positive Test: Yellow precipitate indicates phenols.
Phthalein Dye Test:
Phenols form phthalein dyes when treated with phthalic anhydride and concentrated sulfuric acid.
Positive Test: Appearance of pink/red color after heating indicates phenols.
These tests are not exclusive to phenol and may give positive results for other phenolic compounds. Confirmation may require additional techniques like spectroscopy or chromatography.