An amine X reacts with H₂SO₄ at 453-473 K to form H₂NC₆H₄SO₃H. X is:
Aniline (C₆H₅NH₂) undergoes sulphonation with H₂SO₄ at high temperature to form sulphanilic acid (H₂NC₆H₄SO₃H), as per the PDF.
Ref: NCERT Class 12 Chemistry > Chapter 13: Amines > Topic: Preparation - Hoffmann Bromamide and Reduction of Nitro Compounds