मराठी

Detection of Phenols

Advertisements

Topics

Estimated time: 5 minutes
CBSE: Class 12

Key Points: Detection of Phenols

FeCl₃ Test:

  • Phenol + neutral FeCl₃ solution → violet colour (iron phenoxide complex)

  • Note: m, p-hydroxy benzoic acid and di/trinitrophenols DO NOT give this test; alcohols do not give this test either

Bromine Water Test:

Phenol + Br₂ water → white precipitate of 2,4,6-tribromophenol

Liebermann's Nitroso Reaction:

  • Phenol + NaNO₂ + conc. H₂SO₄ → deep green or blue colour (changes to red on dilution with water; alkaline with NaOH → original green/blue restored)

  • Used as a test for phenol.

Azo dye formation / Azo-dye test:

  • 1° aromatic amines + NaNO₂ + HCl → diazonium salt → coupled with β-naphthol in alkaline solution → orange-red azo dye
  • Also confirms phenols (phenol is the coupling partner)
Advertisements
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×