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JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Practical and Analytical Chemistry

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Phenolic group can be identified by a positive:
  1. (A)Phthalein dye test✓ Correct
  2. (B)Lucas test
  3. (C)Tollen's test
  4. (D)Carbylamine test

Answer: (A)

Solution

Phenols react with phthalic anhydride in concentrated to form phthalein dyes — phenol itself gives phenolphthalein, which turns pink in alkaline solution. This colour reaction, the phthalein dye test, is the characteristic test for a phenolic –OH group. (Lucas' test distinguishes primary, secondary and tertiary alcohols by the rate of turbidity with ; Tollens' test detects aldehydes by silver mirror formation; the carbylamine test detects primary amines through the foul-smelling isocyanide formed with /alcoholic KOH — none of these responds to a phenolic group.)

JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Single correct option

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