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JEE Main · 2026 · 08 Apr 2026 · Shift 2 · Biomolecules

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Which of the following amino acid will give violet coloured complex with neutral ferric chloride solution?
  1. (A)Threonine
  2. (B)Serine
  3. (C)Tyrosine✓ Correct
  4. (D)Cysteine

Answer: (C)

Solution

A violet colour with neutral ferric chloride is the characteristic test for a phenolic hydroxyl group. Among the given amino acids only tyrosine bears a phenolic on its aromatic ring; threonine and serine carry alcoholic hydroxyl groups and cysteine a thiol group, none of which give this colour. Tyrosine produces the violet complex.

JEE Main · 2026 · 08 Apr 2026 · Shift 2 · Single correct option

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