When aniline is heated with conc. H₂SO₄ at 455-475 K, it forms:

• A. Aniline hydrogensulphate
• B. Sulphanilic acid
• C. Amino benzene sulphonic acid
• D. Benzenesulphonic acid

When aniline is heated with concentrated sulfuric acid (H₂SO₄) at temperatures between 455-475 K, the primary product formed is A. Aniline hydrogensulphate. This reaction involves the sulfonation of aniline, leading to the formation of this intermediate compound.

Key Points to Remember

• Aniline is an aromatic amine.
• Concentrated sulfuric acid acts as a sulfonating agent.
• The reaction occurs at elevated temperatures to facilitate the process.

Further Reactions

From aniline hydrogensulphate, further reactions can lead to the formation of other compounds, but the initial product at the specified conditions is indeed aniline hydrogensulphate.